String functions

GoogleSQL supports string functions. These string functions work on two different values: STRING and BYTES data types. STRING values must be well-formed UTF-8.

Functions that return position values, such as STRPOS, encode those positions as INT64. The value 1 refers to the first character (or byte), 2 refers to the second, and so on. The value 0 indicates an invalid position. When working on STRING types, the returned positions refer to character positions.

All string comparisons are done byte-by-byte, without regard to Unicode canonical equivalence.

Function list

ASCII

ASCII(value)

Description

Returns the ASCII code for the first character or byte in value. Returns 0 if value is empty or the ASCII code is 0 for the first character or byte.

Return type

INT64

Examples

SELECT ASCII('abcd') as A, ASCII('a') as B, ASCII('') as C, ASCII(NULL) as D;

/*-------+-------+-------+-------+
 | A     | B     | C     | D     |
 +-------+-------+-------+-------+
 | 97    | 97    | 0     | NULL  |
 +-------+-------+-------+-------*/

BYTE_LENGTH

BYTE_LENGTH(value)

Description

Gets the number of BYTES in a STRING or BYTES value, regardless of whether the value is a STRING or BYTES type.

Return type

INT64

Examples

SELECT BYTE_LENGTH('абвгд') AS string_example;

/*----------------+
 | string_example |
 +----------------+
 | 10             |
 +----------------*/

SELECT BYTE_LENGTH(b'абвгд') AS bytes_example;

/*----------------+
 | bytes_example  |
 +----------------+
 | 10             |
 +----------------*/

CHAR_LENGTH

CHAR_LENGTH(value)

Description

Gets the number of characters in a STRING value.

Return type

INT64

Examples

SELECT CHAR_LENGTH('абвгд') AS char_length;

/*-------------+
 | char_length |
 +-------------+
 | 5           |
 +------------ */

CHARACTER_LENGTH

CHARACTER_LENGTH(value)

Description

Synonym for CHAR_LENGTH.

Return type

INT64

Examples

SELECT
  'абвгд' AS characters,
  CHARACTER_LENGTH('абвгд') AS char_length_example

/*------------+---------------------+
 | characters | char_length_example |
 +------------+---------------------+
 | абвгд      |                   5 |
 +------------+---------------------*/

CHR

CHR(value)

Description

Takes a Unicode code point and returns the character that matches the code point. Each valid code point should fall within the range of [0, 0xD7FF] and [0xE000, 0x10FFFF]. Returns an empty string if the code point is 0. If an invalid Unicode code point is specified, an error is returned.

To work with an array of Unicode code points, see CODE_POINTS_TO_STRING

Return type

STRING

Examples

SELECT CHR(65) AS A, CHR(255) AS B, CHR(513) AS C, CHR(1024)  AS D;

/*-------+-------+-------+-------+
 | A     | B     | C     | D     |
 +-------+-------+-------+-------+
 | A     | ÿ     | ȁ     | Ѐ     |
 +-------+-------+-------+-------*/

SELECT CHR(97) AS A, CHR(0xF9B5) AS B, CHR(0) AS C, CHR(NULL) AS D;

/*-------+-------+-------+-------+
 | A     | B     | C     | D     |
 +-------+-------+-------+-------+
 | a     | 例    |       | NULL  |
 +-------+-------+-------+-------*/

CODE_POINTS_TO_BYTES

CODE_POINTS_TO_BYTES(ascii_code_points)

Description

Takes an array of extended ASCII code points as ARRAY<INT64> and returns BYTES.

To convert from BYTES to an array of code points, see TO_CODE_POINTS.

Return type

BYTES

Examples

The following is a basic example using CODE_POINTS_TO_BYTES.

SELECT CODE_POINTS_TO_BYTES([65, 98, 67, 100]) AS bytes;

/*----------+
 | bytes    |
 +----------+
 | AbCd     |
 +----------*/

The following example uses a rotate-by-13 places (ROT13) algorithm to encode a string.

SELECT CODE_POINTS_TO_BYTES(ARRAY_AGG(
  (SELECT
      CASE
        WHEN chr BETWEEN b'a' and b'z'
          THEN TO_CODE_POINTS(b'a')[offset(0)] +
            MOD(code+13-TO_CODE_POINTS(b'a')[offset(0)],26)
        WHEN chr BETWEEN b'A' and b'Z'
          THEN TO_CODE_POINTS(b'A')[offset(0)] +
            MOD(code+13-TO_CODE_POINTS(b'A')[offset(0)],26)
        ELSE code
      END
   FROM
     (SELECT code, CODE_POINTS_TO_BYTES([code]) chr)
  ) ORDER BY OFFSET)) AS encoded_string
FROM UNNEST(TO_CODE_POINTS(b'Test String!')) code WITH OFFSET;

/*------------------+
 | encoded_string   |
 +------------------+
 | Grfg Fgevat!     |
 +------------------*/

CODE_POINTS_TO_STRING

CODE_POINTS_TO_STRING(unicode_code_points)

Description

Takes an array of Unicode code points as ARRAY<INT64> and returns a STRING.

To convert from a string to an array of code points, see TO_CODE_POINTS.

Return type

STRING

Examples

The following are basic examples using CODE_POINTS_TO_STRING.

SELECT CODE_POINTS_TO_STRING([65, 255, 513, 1024]) AS string;

/*--------+
 | string |
 +--------+
 | AÿȁЀ   |
 +--------*/

SELECT CODE_POINTS_TO_STRING([97, 0, 0xF9B5]) AS string;

/*--------+
 | string |
 +--------+
 | a例    |
 +--------*/

SELECT CODE_POINTS_TO_STRING([65, 255, NULL, 1024]) AS string;

/*--------+
 | string |
 +--------+
 | NULL   |
 +--------*/

The following example computes the frequency of letters in a set of words.

WITH Words AS (
  SELECT word
  FROM UNNEST(['foo', 'bar', 'baz', 'giraffe', 'llama']) AS word
)
SELECT
  CODE_POINTS_TO_STRING([code_point]) AS letter,
  COUNT(*) AS letter_count
FROM Words,
  UNNEST(TO_CODE_POINTS(word)) AS code_point
GROUP BY 1
ORDER BY 2 DESC;

/*--------+--------------+
 | letter | letter_count |
 +--------+--------------+
 | a      | 5            |
 | f      | 3            |
 | r      | 2            |
 | b      | 2            |
 | l      | 2            |
 | o      | 2            |
 | g      | 1            |
 | z      | 1            |
 | e      | 1            |
 | m      | 1            |
 | i      | 1            |
 +--------+--------------*/

COLLATE

COLLATE(value, collate_specification)

Takes a STRING and a collation specification. Returns a STRING with a collation specification. If collate_specification is empty, returns a value with collation removed from the STRING.

The collation specification defines how the resulting STRING can be compared and sorted. To learn more, see Collation.

• collation_specification must be a string literal, otherwise an error is thrown.
• Returns NULL if value is NULL.

Return type

STRING

Examples

In this example, the weight of a is less than the weight of Z. This is because the collate specification, und:ci assigns more weight to Z.

WITH Words AS (
  SELECT
    COLLATE('a', 'und:ci') AS char1,
    COLLATE('Z', 'und:ci') AS char2
)
SELECT ( Words.char1 < Words.char2 ) AS a_less_than_Z
FROM Words;

/*----------------+
 | a_less_than_Z  |
 +----------------+
 | TRUE           |
 +----------------*/

In this example, the weight of a is greater than the weight of Z. This is because the default collate specification assigns more weight to a.

WITH Words AS (
  SELECT
    'a' AS char1,
    'Z' AS char2
)
SELECT ( Words.char1 < Words.char2 ) AS a_less_than_Z
FROM Words;

/*----------------+
 | a_less_than_Z  |
 +----------------+
 | FALSE          |
 +----------------*/

CONCAT

CONCAT(value1[, ...])

Description

Concatenates one or more values into a single result. All values must be BYTES or data types that can be cast to STRING.

The function returns NULL if any input argument is NULL.

Note: You can also use the || concatenation operator to concatenate values into a string.

Return type

STRING or BYTES

Examples

SELECT CONCAT('T.P.', ' ', 'Bar') as author;

/*---------------------+
 | author              |
 +---------------------+
 | T.P. Bar            |
 +---------------------*/

SELECT CONCAT('Summer', ' ', 1923) as release_date;

/*---------------------+
 | release_date        |
 +---------------------+
 | Summer 1923         |
 +---------------------*/

With Employees AS
  (SELECT
    'John' AS first_name,
    'Doe' AS last_name
  UNION ALL
  SELECT
    'Jane' AS first_name,
    'Smith' AS last_name
  UNION ALL
  SELECT
    'Joe' AS first_name,
    'Jackson' AS last_name)

SELECT
  CONCAT(first_name, ' ', last_name)
  AS full_name
FROM Employees;

/*---------------------+
 | full_name           |
 +---------------------+
 | John Doe            |
 | Jane Smith          |
 | Joe Jackson         |
 +---------------------*/

EDIT_DISTANCE

EDIT_DISTANCE(
  value1,
  value2,
  [ max_distance => max_distance_value ]
)

Description

Computes the Levenshtein distance between two STRING or BYTES values.

Definitions

• value1: The first STRING or BYTES value to compare.

• value2: The second STRING or BYTES value to compare.

• max_distance: A named argument with a INT64 value that's greater than or equal to zero. Represents the maximum distance between the two values to compute.

  If this distance is exceeded, the function returns this value. The default value for this argument is the maximum size of value1 and value2.

Details

If value1 or value2 is NULL, NULL is returned.

You can only compare values of the same type. Otherwise, an error is produced.

Return type

INT64

Examples

In the following example, the first character in both strings is different:

SELECT EDIT_DISTANCE('a', 'b') AS results;

/*---------+
 | results |
 +---------+
 | 1       |
 +---------*/

In the following example, the first and second characters in both strings are different:

SELECT EDIT_DISTANCE('aa', 'b') AS results;

/*---------+
 | results |
 +---------+
 | 2       |
 +---------*/

In the following example, only the first character in both strings is different:

SELECT EDIT_DISTANCE('aa', 'ba') AS results;

/*---------+
 | results |
 +---------+
 | 1       |
 +---------*/

In the following example, the last six characters are different, but because the maximum distance is 2, this function exits early and returns 2, the maximum distance:

SELECT EDIT_DISTANCE('abcdefg', 'a', max_distance => 2) AS results;

/*---------+
 | results |
 +---------+
 | 2       |
 +---------*/

ENDS_WITH

ENDS_WITH(value, suffix)

Description

Takes two STRING or BYTES values. Returns TRUE if suffix is a suffix of value.

This function supports specifying collation.

Return type

BOOL

Examples

SELECT ENDS_WITH('apple', 'e') as example

/*---------+
 | example |
 +---------+
 |    True |
 +---------*/

FORMAT

FORMAT(format_string_expression, data_type_expression[, ...])

Description

FORMAT formats a data type expression as a string.

• format_string_expression: Can contain zero or more format specifiers. Each format specifier is introduced by the % symbol, and must map to one or more of the remaining arguments. In general, this is a one-to-one mapping, except when the * specifier is present. For example, %.*i maps to two arguments—a length argument and a signed integer argument. If the number of arguments related to the format specifiers isn't the same as the number of arguments, an error occurs.
• data_type_expression: The value to format as a string. This can be any GoogleSQL data type.

Return type

STRING

Examples

The FORMAT() function doesn't provide fully customizable formatting for all types and values, nor formatting that's sensitive to locale.

If custom formatting is necessary for a type, you must first format it using type-specific format functions, such as FORMAT_DATE() or FORMAT_TIMESTAMP(). For example:

SELECT FORMAT('date: %s!', FORMAT_DATE('%B %d, %Y', date '2015-01-02'));

Returns

date: January 02, 2015!

Supported format specifiers

%[flags][width][.precision]specifier

A format specifier adds formatting when casting a value to a string. It can optionally contain these sub-specifiers:

• Flags
• Width
• Precision

Additional information about format specifiers:

• %g and %G behavior
• %p and %P behavior
• %t and %T behavior
• Error conditions
• NULL argument handling
• Additional semantic rules

Format specifiers

</td>

  Produces a one-line printable string representing a protocol buffer
  or JSON.
  
  See <a href="#p_and_p_behavior">%p and %P behavior</a>.
</td>
<td>
  

year: 2019 month: 10

{"month":10,"year":2019}

</td>
<td>

  Produces a multi-line printable string representing a protocol buffer
  or JSON.
  
  See <a href="#p_and_p_behavior">%p and %P behavior</a>.
</td>
<td>
  

year: 2019
month: 10

{
  "month": 10,
  "year": 2019
}

</td>
<td>

The format specifier can optionally contain the sub-specifiers identified above in the specifier prototype.

These sub-specifiers must comply with the following specifications.

Flags

Flags may be specified in any order. Duplicate flags aren't an error. When flags aren't relevant for some element type, they are ignored.

Width

Precision

%g and %G behavior

The %g and %G format specifiers choose either the decimal notation (like the %f and %F specifiers) or the scientific notation (like the %e and %E specifiers), depending on the input value's exponent and the specified precision.

Let p stand for the specified precision (defaults to 6; 1 if the specified precision is less than 1). The input value is first converted to scientific notation with precision = (p - 1). If the resulting exponent part x is less than -4 or no less than p, the scientific notation with precision = (p - 1) is used; otherwise the decimal notation with precision = (p - 1 - x) is used.

Unless # flag is present, the trailing zeros after the decimal point are removed, and the decimal point is also removed if there is no digit after it.

%p and %P behavior

The %p format specifier produces a one-line printable string. The %P format specifier produces a multi-line printable string. You can use these format specifiers with the following data types:

message ReleaseDate {
 required int32 year = 1 [default=2019];
 required int32 month = 2 [default=10];
}

year: 2019 month: 10

message ReleaseDate {
 required int32 year = 1 [default=2019];
 required int32 month = 2 [default=10];
}

year: 2019
month: 10

JSON '
{
  "month": 10,
  "year": 2019
}
'

{"month":10,"year":2019}

JSON '
{
  "month": 10,
  "year": 2019
}
'

{
  "month": 10,
  "year": 2019
}

%t and %T behavior

The %t and %T format specifiers are defined for all types. The width, precision, and flags act as they do for %s: the width is the minimum width and the STRING will be padded to that size, and precision is the maximum width of content to show and the STRING will be truncated to that size, prior to padding to width.

The %t specifier is always meant to be a readable form of the value.

The %T specifier is always a valid SQL literal of a similar type, such as a wider numeric type. The literal will not include casts or a type name, except for the special case of non-finite floating point values.

The STRING is formatted as follows:

<td>FLOAT, DOUBLE</td>

<td>
  123.0  <em>(always with .0)</em><br/>
  123e+10<br/>
  <code>inf</code><br/>
  <code>-inf</code><br/>
  <code>NaN</code>
</td>
<td>
  123.0  <em>(always with .0)</em><br/>
  123e+10<br/>
  CAST("inf" AS &lt;type&gt;)<br/>
  CAST("-inf" AS &lt;type&gt;)<br/>
  CAST("nan" AS &lt;type&gt;)
</td>

{"name":"apple","stock":3}

JSON '{"name":"apple","stock":3}'

Error conditions

If a format specifier is invalid, or isn't compatible with the related argument type, or the wrong number or arguments are provided, then an error is produced. For example, the following <format_string> expressions are invalid:

FORMAT('%s', 1)

FORMAT('%')

NULL argument handling

A NULL format string results in a NULL output STRING. Any other arguments are ignored in this case.

The function generally produces a NULL value if a NULL argument is present. For example, FORMAT('%i', NULL_expression) produces a NULL STRING as output.

However, there are some exceptions: if the format specifier is %t or %T (both of which produce STRINGs that effectively match CAST and literal value semantics), a NULL value produces 'NULL' (without the quotes) in the result STRING. For example, the function:

FORMAT('00-%t-00', NULL_expression);

Returns

00-NULL-00

Additional semantic rules

DOUBLE and FLOAT values can be +/-inf or NaN. When an argument has one of those values, the result of the format specifiers %f, %F, %e, %E, %g, %G, and %t are inf, -inf, or nan (or the same in uppercase) as appropriate. This is consistent with how GoogleSQL casts these values to STRING. For %T, GoogleSQL returns quoted strings for DOUBLE values that don't have non-string literal representations.

FROM_BASE32

FROM_BASE32(string_expr)

Description

Converts the base32-encoded input string_expr into BYTES format. To convert BYTES to a base32-encoded STRING, use TO_BASE32.

Return type

BYTES

Example

SELECT FROM_BASE32('MFRGGZDF74======') AS byte_data;

/*-----------+
 | byte_data |
 +-----------+
 | abcde\xff |
 +-----------*/

FROM_BASE64

FROM_BASE64(string_expr)

Description

Converts the base64-encoded input string_expr into BYTES format. To convert BYTES to a base64-encoded STRING, use TO_BASE64.

There are several base64 encodings in common use that vary in exactly which alphabet of 65 ASCII characters are used to encode the 64 digits and padding. See RFC 4648 for details. This function expects the alphabet [A-Za-z0-9+/=].

Return type

BYTES

Example

SELECT FROM_BASE64('/+A=') AS byte_data;

/*-----------+
 | byte_data |
 +-----------+
 | \377\340  |
 +-----------*/

To work with an encoding using a different base64 alphabet, you might need to compose FROM_BASE64 with the REPLACE function. For instance, the base64url url-safe and filename-safe encoding commonly used in web programming uses -_= as the last characters rather than +/=. To decode a base64url-encoded string, replace - and _ with + and / respectively.

SELECT FROM_BASE64(REPLACE(REPLACE('_-A=', '-', '+'), '_', '/')) AS binary;

/*-----------+
 | binary    |
 +-----------+
 | \377\340  |
 +-----------*/

FROM_HEX

FROM_HEX(string)

Description

Converts a hexadecimal-encoded STRING into BYTES format. Returns an error if the input STRING contains characters outside the range (0..9, A..F, a..f). The lettercase of the characters doesn't matter. If the input STRING has an odd number of characters, the function acts as if the input has an additional leading 0. To convert BYTES to a hexadecimal-encoded STRING, use TO_HEX.

Return type

BYTES

Example

WITH Input AS (
  SELECT '00010203aaeeefff' AS hex_str UNION ALL
  SELECT '0AF' UNION ALL
  SELECT '666f6f626172'
)
SELECT hex_str, FROM_HEX(hex_str) AS bytes_str
FROM Input;

/*------------------+----------------------------------+
 | hex_str          | bytes_str                        |
 +------------------+----------------------------------+
 | 0AF              | \x00\xaf                         |
 | 00010203aaeeefff | \x00\x01\x02\x03\xaa\xee\xef\xff |
 | 666f6f626172     | foobar                           |
 +------------------+----------------------------------*/

INITCAP

INITCAP(value[, delimiters])

Description

Takes a STRING and returns it with the first character in each word in uppercase and all other characters in lowercase. Non-alphabetic characters remain the same.

delimiters is an optional string argument that's used to override the default set of characters used to separate words. If delimiters isn't specified, it defaults to the following characters:
<whitespace> [ ] ( ) { } / | \ < > ! ? @ " ^ # $ & ~ _ , . : ; * % + -

If value or delimiters is NULL, the function returns NULL.

Return type

STRING

Examples

SELECT
  'Hello World-everyone!' AS value,
  INITCAP('Hello World-everyone!') AS initcap_value

/*-------------------------------+-------------------------------+
 | value                         | initcap_value                 |
 +-------------------------------+-------------------------------+
 | Hello World-everyone!         | Hello World-Everyone!         |
 +-------------------------------+-------------------------------*/

SELECT
  'Apples1oranges2pears' as value,
  '12' AS delimiters,
  INITCAP('Apples1oranges2pears' , '12') AS initcap_value

/*----------------------+------------+----------------------+
 | value                | delimiters | initcap_value        |
 +----------------------+------------+----------------------+
 | Apples1oranges2pears | 12         | Apples1Oranges2Pears |
 +----------------------+------------+----------------------*/

INSTR

INSTR(value, subvalue[, position[, occurrence]])

Description

Returns the lowest 1-based position of subvalue in value. value and subvalue must be the same type, either STRING or BYTES.

If position is specified, the search starts at this position in value, otherwise it starts at 1, which is the beginning of value. If position is negative, the function searches backwards from the end of value, with -1 indicating the last character. position is of type INT64 and can't be 0.

If occurrence is specified, the search returns the position of a specific instance of subvalue in value. If not specified, occurrence defaults to 1 and returns the position of the first occurrence. For occurrence > 1, the function includes overlapping occurrences. occurrence is of type INT64 and must be positive.

This function supports specifying collation.

Returns 0 if:

• No match is found.
• If occurrence is greater than the number of matches found.
• If position is greater than the length of value.

Returns NULL if:

• Any input argument is NULL.

Returns an error if:

• position is 0.
• occurrence is 0 or negative.

Return type

INT64

Examples

SELECT
  'banana' AS value, 'an' AS subvalue, 1 AS position, 1 AS occurrence,
  INSTR('banana', 'an', 1, 1) AS instr;

/*--------------+--------------+----------+------------+-------+
 | value        | subvalue     | position | occurrence | instr |
 +--------------+--------------+----------+------------+-------+
 | banana       | an           | 1        | 1          | 2     |
 +--------------+--------------+----------+------------+-------*/

SELECT
  'banana' AS value, 'an' AS subvalue, 1 AS position, 2 AS occurrence,
  INSTR('banana', 'an', 1, 2) AS instr;

/*--------------+--------------+----------+------------+-------+
 | value        | subvalue     | position | occurrence | instr |
 +--------------+--------------+----------+------------+-------+
 | banana       | an           | 1        | 2          | 4     |
 +--------------+--------------+----------+------------+-------*/

SELECT
  'banana' AS value, 'an' AS subvalue, 1 AS position, 3 AS occurrence,
  INSTR('banana', 'an', 1, 3) AS instr;

/*--------------+--------------+----------+------------+-------+
 | value        | subvalue     | position | occurrence | instr |
 +--------------+--------------+----------+------------+-------+
 | banana       | an           | 1        | 3          | 0     |
 +--------------+--------------+----------+------------+-------*/

SELECT
  'banana' AS value, 'an' AS subvalue, 3 AS position, 1 AS occurrence,
  INSTR('banana', 'an', 3, 1) AS instr;

/*--------------+--------------+----------+------------+-------+
 | value        | subvalue     | position | occurrence | instr |
 +--------------+--------------+----------+------------+-------+
 | banana       | an           | 3        | 1          | 4     |
 +--------------+--------------+----------+------------+-------*/

SELECT
  'banana' AS value, 'an' AS subvalue, -1 AS position, 1 AS occurrence,
  INSTR('banana', 'an', -1, 1) AS instr;

/*--------------+--------------+----------+------------+-------+
 | value        | subvalue     | position | occurrence | instr |
 +--------------+--------------+----------+------------+-------+
 | banana       | an           | -1       | 1          | 4     |
 +--------------+--------------+----------+------------+-------*/

SELECT
  'banana' AS value, 'an' AS subvalue, -3 AS position, 1 AS occurrence,
  INSTR('banana', 'an', -3, 1) AS instr;

/*--------------+--------------+----------+------------+-------+
 | value        | subvalue     | position | occurrence | instr |
 +--------------+--------------+----------+------------+-------+
 | banana       | an           | -3       | 1          | 4     |
 +--------------+--------------+----------+------------+-------*/

SELECT
  'banana' AS value, 'ann' AS subvalue, 1 AS position, 1 AS occurrence,
  INSTR('banana', 'ann', 1, 1) AS instr;

/*--------------+--------------+----------+------------+-------+
 | value        | subvalue     | position | occurrence | instr |
 +--------------+--------------+----------+------------+-------+
 | banana       | ann          | 1        | 1          | 0     |
 +--------------+--------------+----------+------------+-------*/

SELECT
  'helloooo' AS value, 'oo' AS subvalue, 1 AS position, 1 AS occurrence,
  INSTR('helloooo', 'oo', 1, 1) AS instr;

/*--------------+--------------+----------+------------+-------+
 | value        | subvalue     | position | occurrence | instr |
 +--------------+--------------+----------+------------+-------+
 | helloooo     | oo           | 1        | 1          | 5     |
 +--------------+--------------+----------+------------+-------*/

SELECT
  'helloooo' AS value, 'oo' AS subvalue, 1 AS position, 2 AS occurrence,
  INSTR('helloooo', 'oo', 1, 2) AS instr;

/*--------------+--------------+----------+------------+-------+
 | value        | subvalue     | position | occurrence | instr |
 +--------------+--------------+----------+------------+-------+
 | helloooo     | oo           | 1        | 2          | 6     |
 +--------------+--------------+----------+------------+-------*/

LEFT

LEFT(value, length)

Description

Returns a STRING or BYTES value that consists of the specified number of leftmost characters or bytes from value. The length is an INT64 that specifies the length of the returned value. If value is of type BYTES, length is the number of leftmost bytes to return. If value is STRING, length is the number of leftmost characters to return.

If length is 0, an empty STRING or BYTES value will be returned. If length is negative, an error will be returned. If length exceeds the number of characters or bytes from value, the original value will be returned.

Return type

STRING or BYTES

Examples

SELECT LEFT('banana', 3) AS results

/*---------+
 | results |
  +--------+
 | ban     |
 +---------*/

SELECT LEFT(b'\xab\xcd\xef\xaa\xbb', 3) AS results

/*--------------+
 | results      |
 +--------------+
 | \xab\xcd\xef |
 +--------------*/

LENGTH

LENGTH(value)

Description

Returns the length of the STRING or BYTES value. The returned value is in characters for STRING arguments and in bytes for the BYTES argument.

Return type

INT64

Examples

SELECT
  LENGTH('абвгд') AS string_example,
  LENGTH(CAST('абвгд' AS BYTES)) AS bytes_example;

/*----------------+---------------+
 | string_example | bytes_example |
 +----------------+---------------+
 | 5              | 10            |
 +----------------+---------------*/

LOWER

LOWER(value)

Description

For STRING arguments, returns the original string with all alphabetic characters in lowercase. Mapping between lowercase and uppercase is done according to the Unicode Character Database without taking into account language-specific mappings.

For BYTES arguments, the argument is treated as ASCII text, with all bytes greater than 127 left intact.

Return type

STRING or BYTES

Examples

SELECT
  LOWER('FOO BAR BAZ') AS example
FROM items;

/*-------------+
 | example     |
 +-------------+
 | foo bar baz |
 +-------------*/

LPAD

LPAD(original_value, return_length[, pattern])

Description

Returns a STRING or BYTES value that consists of original_value prepended with pattern. The return_length is an INT64 that specifies the length of the returned value. If original_value is of type BYTES, return_length is the number of bytes. If original_value is of type STRING, return_length is the number of characters.

The default value of pattern is a blank space.

Both original_value and pattern must be the same data type.

If return_length is less than or equal to the original_value length, this function returns the original_value value, truncated to the value of return_length. For example, LPAD('hello world', 7); returns 'hello w'.

If original_value, return_length, or pattern is NULL, this function returns NULL.

This function returns an error if:

• return_length is negative
• pattern is empty

Return type

STRING or BYTES

Examples

SELECT FORMAT('%T', LPAD('c', 5)) AS results

/*---------+
 | results |
 +---------+
 | "    c" |
 +---------*/

SELECT LPAD('b', 5, 'a') AS results

/*---------+
 | results |
 +---------+
 | aaaab   |
 +---------*/

SELECT LPAD('abc', 10, 'ghd') AS results

/*------------+
 | results    |
 +------------+
 | ghdghdgabc |
 +------------*/

SELECT LPAD('abc', 2, 'd') AS results

/*---------+
 | results |
 +---------+
 | ab      |
 +---------*/

SELECT FORMAT('%T', LPAD(b'abc', 10, b'ghd')) AS results

/*---------------+
 | results       |
 +---------------+
 | b"ghdghdgabc" |
 +---------------*/

LTRIM

LTRIM(value1[, value2])

Description

Identical to TRIM, but only removes leading characters.

Return type

STRING or BYTES

Examples

SELECT CONCAT('#', LTRIM('   apple   '), '#') AS example

/*-------------+
 | example     |
 +-------------+
 | #apple   #  |
 +-------------*/

SELECT LTRIM('***apple***', '*') AS example

/*-----------+
 | example   |
 +-----------+
 | apple***  |
 +-----------*/

SELECT LTRIM('xxxapplexxx', 'xyz') AS example

/*-----------+
 | example   |
 +-----------+
 | applexxx  |
 +-----------*/

NORMALIZE

NORMALIZE(value[, normalization_mode])

Description

Takes a string value and returns it as a normalized string. If you don't provide a normalization mode, NFC is used.

Normalization is used to ensure that two strings are equivalent. Normalization is often used in situations in which two strings render the same on the screen but have different Unicode code points.

NORMALIZE supports four optional normalization modes:

Return type

STRING

Examples

The following example normalizes different language characters:

SELECT
  NORMALIZE('\u00ea') as a,
  NORMALIZE('\u0065\u0302') as b,
  NORMALIZE('\u00ea') = NORMALIZE('\u0065\u0302') as normalized;

/*---+---+------------+
 | a | b | normalized |
 +---+---+------------+
 | ê | ê | TRUE       |
 +---+---+------------*/

The following examples normalize different space characters:

SELECT NORMALIZE('Raha\u2004Mahan', NFKC) AS normalized_name

/*-----------------+
 | normalized_name |
 +-----------------+
 | Raha Mahan      |
 +-----------------*/

SELECT NORMALIZE('Raha\u2005Mahan', NFKC) AS normalized_name

/*-----------------+
 | normalized_name |
 +-----------------+
 | Raha Mahan      |
 +-----------------*/

SELECT NORMALIZE('Raha\u2006Mahan', NFKC) AS normalized_name

/*-----------------+
 | normalized_name |
 +-----------------+
 | Raha Mahan      |
 +-----------------*/

SELECT NORMALIZE('Raha Mahan', NFKC) AS normalized_name

/*-----------------+
 | normalized_name |
 +-----------------+
 | Raha Mahan      |
 +-----------------*/

NORMALIZE_AND_CASEFOLD

NORMALIZE_AND_CASEFOLD(value[, normalization_mode])

Description

Takes a string value and returns it as a normalized string. If you don't provide a normalization mode, NFC is used.

Normalization is used to ensure that two strings are equivalent. Normalization is often used in situations in which two strings render the same on the screen but have different Unicode code points.

Case folding is used for the caseless comparison of strings. If you need to compare strings and case shouldn't be considered, use NORMALIZE_AND_CASEFOLD, otherwise use NORMALIZE.

NORMALIZE_AND_CASEFOLD supports four optional normalization modes:

Return type

STRING

Examples

SELECT
  NORMALIZE('The red barn') = NORMALIZE('The Red Barn') AS normalized,
  NORMALIZE_AND_CASEFOLD('The red barn')
    = NORMALIZE_AND_CASEFOLD('The Red Barn') AS normalized_with_case_folding;

/*------------+------------------------------+
 | normalized | normalized_with_case_folding |
 +------------+------------------------------+
 | FALSE      | TRUE                         |
 +------------+------------------------------*/

SELECT
  '\u2168' AS a,
  'IX' AS b,
  NORMALIZE_AND_CASEFOLD('\u2168', NFD)=NORMALIZE_AND_CASEFOLD('IX', NFD) AS nfd,
  NORMALIZE_AND_CASEFOLD('\u2168', NFC)=NORMALIZE_AND_CASEFOLD('IX', NFC) AS nfc,
  NORMALIZE_AND_CASEFOLD('\u2168', NFKD)=NORMALIZE_AND_CASEFOLD('IX', NFKD) AS nfkd,
  NORMALIZE_AND_CASEFOLD('\u2168', NFKC)=NORMALIZE_AND_CASEFOLD('IX', NFKC) AS nfkc;

/*---+----+-------+-------+------+------+
 | a | b  | nfd   | nfc   | nfkd | nfkc |
 +---+----+-------+-------+------+------+
 | Ⅸ | IX | false | false | true | true |
 +---+----+-------+-------+------+------*/

SELECT
  '\u0041\u030A' AS a,
  '\u00C5' AS b,
  NORMALIZE_AND_CASEFOLD('\u0041\u030A', NFD)=NORMALIZE_AND_CASEFOLD('\u00C5', NFD) AS nfd,
  NORMALIZE_AND_CASEFOLD('\u0041\u030A', NFC)=NORMALIZE_AND_CASEFOLD('\u00C5', NFC) AS nfc,
  NORMALIZE_AND_CASEFOLD('\u0041\u030A', NFKD)=NORMALIZE_AND_CASEFOLD('\u00C5', NFKD) AS nkfd,
  NORMALIZE_AND_CASEFOLD('\u0041\u030A', NFKC)=NORMALIZE_AND_CASEFOLD('\u00C5', NFKC) AS nkfc;

/*---+----+-------+-------+------+------+
 | a | b  | nfd   | nfc   | nkfd | nkfc |
 +---+----+-------+-------+------+------+
 | Å | Å  | true  | true  | true | true |
 +---+----+-------+-------+------+------*/

OCTET_LENGTH

OCTET_LENGTH(value)

Alias for BYTE_LENGTH.

REGEXP_CONTAINS

REGEXP_CONTAINS(value, regexp)

Description

Returns TRUE if value is a partial match for the regular expression, regexp.

If the regexp argument is invalid, the function returns an error.

You can search for a full match by using ^ (beginning of text) and $ (end of text). Due to regular expression operator precedence, it's good practice to use parentheses around everything between ^ and $.

Note: GoogleSQL provides regular expression support using the re2 library; see that documentation for its regular expression syntax.

Return type

BOOL

Examples

The following queries check to see if an email is valid:

SELECT
  'foo@example.com' AS email,
  REGEXP_CONTAINS('foo@example.com', r'@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+') AS is_valid

/*-----------------+----------+
 | email           | is_valid |
 +-----------------+----------+
 | foo@example.com | TRUE     |
 +-----------------+----------*/

SELECT
 'www.example.net' AS email,
 REGEXP_CONTAINS('www.example.net', r'@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+') AS is_valid

/*-----------------+----------+
| email           | is_valid |
+-----------------+----------+
| www.example.net | FALSE    |
+-----------------+----------*/

The following queries check to see if an email is valid. They perform a full match, using ^ and $. Due to regular expression operator precedence, it's good practice to use parentheses around everything between ^ and $.

SELECT
  'a@foo.com' AS email,
  REGEXP_CONTAINS('a@foo.com', r'^([\w.+-]+@foo\.com|[\w.+-]+@bar\.org)$') AS valid_email_address,
  REGEXP_CONTAINS('a@foo.com', r'^[\w.+-]+@foo\.com|[\w.+-]+@bar\.org$') AS without_parentheses;

/*----------------+---------------------+---------------------+
 | email          | valid_email_address | without_parentheses |
 +----------------+---------------------+---------------------+
 | a@foo.com      | true                | true                |
 +----------------+---------------------+---------------------*/

SELECT
  'a@foo.computer' AS email,
  REGEXP_CONTAINS('a@foo.computer', r'^([\w.+-]+@foo\.com|[\w.+-]+@bar\.org)$') AS valid_email_address,
  REGEXP_CONTAINS('a@foo.computer', r'^[\w.+-]+@foo\.com|[\w.+-]+@bar\.org$') AS without_parentheses;

/*----------------+---------------------+---------------------+
 | email          | valid_email_address | without_parentheses |
 +----------------+---------------------+---------------------+
 | a@foo.computer | false               | true                |
 +----------------+---------------------+---------------------*/

SELECT
  'b@bar.org' AS email,
  REGEXP_CONTAINS('b@bar.org', r'^([\w.+-]+@foo\.com|[\w.+-]+@bar\.org)$') AS valid_email_address,
  REGEXP_CONTAINS('b@bar.org', r'^[\w.+-]+@foo\.com|[\w.+-]+@bar\.org$') AS without_parentheses;

/*----------------+---------------------+---------------------+
 | email          | valid_email_address | without_parentheses |
 +----------------+---------------------+---------------------+
 | b@bar.org      | true                | true                |
 +----------------+---------------------+---------------------*/

SELECT
  '!b@bar.org' AS email,
  REGEXP_CONTAINS('!b@bar.org', r'^([\w.+-]+@foo\.com|[\w.+-]+@bar\.org)$') AS valid_email_address,
  REGEXP_CONTAINS('!b@bar.org', r'^[\w.+-]+@foo\.com|[\w.+-]+@bar\.org$') AS without_parentheses;

/*----------------+---------------------+---------------------+
 | email          | valid_email_address | without_parentheses |
 +----------------+---------------------+---------------------+
 | !b@bar.org     | false               | true                |
 +----------------+---------------------+---------------------*/

SELECT
  'c@buz.net' AS email,
  REGEXP_CONTAINS('c@buz.net', r'^([\w.+-]+@foo\.com|[\w.+-]+@bar\.org)$') AS valid_email_address,
  REGEXP_CONTAINS('c@buz.net', r'^[\w.+-]+@foo\.com|[\w.+-]+@bar\.org$') AS without_parentheses;

/*----------------+---------------------+---------------------+
 | email          | valid_email_address | without_parentheses |
 +----------------+---------------------+---------------------+
 | c@buz.net      | false               | false               |
 +----------------+---------------------+---------------------*/

REGEXP_EXTRACT

REGEXP_EXTRACT(value, regexp[, position[, occurrence]])

Description

Returns the substring in value that matches the re2 regular expression, regexp. Returns NULL if there is no match.

If the regular expression contains a capturing group ((...)), and there is a match for that capturing group, that match is returned. If there are multiple matches for a capturing group, the first match is returned.

To extract matches for multiple capturing groups in a single call, use REGEXP_EXTRACT_GROUPS.

If position is specified, the search starts at this position in value, otherwise it starts at the beginning of value. The position must be a positive integer and can't be 0. If position is greater than the length of value, NULL is returned.

If occurrence is specified, the search returns a specific occurrence of the regexp in value, otherwise returns the first match. If occurrence is greater than the number of matches found, NULL is returned. For occurrence > 1, the function searches for additional occurrences beginning with the character following the previous occurrence.

Returns an error if:

• The regular expression is invalid
• The regular expression has more than one capturing group
• The position isn't a positive integer
• The occurrence isn't a positive integer

Return type

STRING or BYTES

Examples

SELECT REGEXP_EXTRACT('foo@example.com', r'^[a-zA-Z0-9_.+-]+') AS user_name

/*-----------+
 | user_name |
 +-----------+
 | foo       |
 +-----------*/

SELECT REGEXP_EXTRACT('foo@example.com', r'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.([a-zA-Z0-9-.]+$)')

/*------------------+
 | top_level_domain |
 +------------------+
 | com              |
 +------------------*/

SELECT
  REGEXP_EXTRACT('ab', '.b') AS result_a,
  REGEXP_EXTRACT('ab', '(.)b') AS result_b,
  REGEXP_EXTRACT('xyztb', '(.)+b') AS result_c,
  REGEXP_EXTRACT('ab', '(z)?b') AS result_d

/*-------------------------------------------+
 | result_a | result_b | result_c | result_d |
 +-------------------------------------------+
 | ab       | a        | t        | NULL     |
 +-------------------------------------------*/

WITH example AS
(SELECT 'Hello Helloo and Hellooo' AS value, 'H?ello+' AS regex, 1 as position,
1 AS occurrence UNION ALL
SELECT 'Hello Helloo and Hellooo', 'H?ello+', 1, 2 UNION ALL
SELECT 'Hello Helloo and Hellooo', 'H?ello+', 1, 3 UNION ALL
SELECT 'Hello Helloo and Hellooo', 'H?ello+', 1, 4 UNION ALL
SELECT 'Hello Helloo and Hellooo', 'H?ello+', 2, 1 UNION ALL
SELECT 'Hello Helloo and Hellooo', 'H?ello+', 3, 1 UNION ALL
SELECT 'Hello Helloo and Hellooo', 'H?ello+', 3, 2 UNION ALL
SELECT 'Hello Helloo and Hellooo', 'H?ello+', 3, 3 UNION ALL
SELECT 'Hello Helloo and Hellooo', 'H?ello+', 20, 1 UNION ALL
SELECT 'cats&dogs&rabbits' ,'\\w+&', 1, 2 UNION ALL
SELECT 'cats&dogs&rabbits', '\\w+&', 2, 3
)
SELECT value, regex, position, occurrence, REGEXP_EXTRACT(value, regex,
position, occurrence) AS regexp_value FROM example;

/*--------------------------+---------+----------+------------+--------------+
 | value                    | regex   | position | occurrence | regexp_value |
 +--------------------------+---------+----------+------------+--------------+
 | Hello Helloo and Hellooo | H?ello+ | 1        | 1          | Hello        |
 | Hello Helloo and Hellooo | H?ello+ | 1        | 2          | Helloo       |
 | Hello Helloo and Hellooo | H?ello+ | 1        | 3          | Hellooo      |
 | Hello Helloo and Hellooo | H?ello+ | 1        | 4          | NULL         |
 | Hello Helloo and Hellooo | H?ello+ | 2        | 1          | ello         |
 | Hello Helloo and Hellooo | H?ello+ | 3        | 1          | Helloo       |
 | Hello Helloo and Hellooo | H?ello+ | 3        | 2          | Hellooo      |
 | Hello Helloo and Hellooo | H?ello+ | 3        | 3          | NULL         |
 | Hello Helloo and Hellooo | H?ello+ | 20       | 1          | NULL         |
 | cats&dogs&rabbits        | \w+&    | 1        | 2          | dogs&        |
 | cats&dogs&rabbits        | \w+&    | 2        | 3          | NULL         |
 +--------------------------+---------+----------+------------+--------------*/

REGEXP_EXTRACT_GROUPS

REGEXP_EXTRACT_GROUPS(value, regexp)

Description

Returns a STRUCT where each field contains a substring from value that matches a capturing group in the re2 regular expression, regexp. The function returns the substrings from the first place in value where the entire regexp pattern matches.

Details

This function is similar to REGEXP_EXTRACT, but it returns a STRUCT with a field for each capturing group in the regexp.

The regexp must contain at least one capturing group. The fields in the returned STRUCT correspond to these capturing groups:

• If a capturing group is named (for example, (?<name>...) or (?P<name>...)), the corresponding STRUCT field will have that name. Both syntaxes are equivalent.
• If a capturing group is unnamed, the corresponding STRUCT field is anonymous. These fields can be accessed by their 0-based position in the STRUCT.
• The order of fields in the STRUCT matches the order of the capturing groups in regexp from left to right.

Returns NULL if value is NULL or if the overall regexp pattern doesn't match at all. If a specific capturing group doesn't match (for example, if it's part of an alternation or is optional), the corresponding STRUCT field is NULL.

Returns an error if:

• The regexp is invalid.
• The regexp is not a string literal.
• The regexp has no capturing groups.
• A capturing group name is not a valid STRUCT field name (for example, starts with a digit or contains spaces). Valid names consist of letters, numbers, and underscores, and must start with a letter or underscore.
• The same capturing group name is used more than once (case-insensitive).

Return type

STRUCT<...>

The fields of the STRUCT are generally STRING (or BYTES if the inputs are BYTES). However, fields can be auto-casted to other types.

Examples

Extract unnamed groups:

SELECT REGEXP_EXTRACT_GROUPS('abc123xyz', r'([a-z]+)([0-9]+)([a-z]+)') AS result

/*---------------------------------+
 | result                          |
 +---------------------------------+
 | {abc, 123, xyz}                 |
 +---------------------------------*/

Extract named groups:

SELECT REGEXP_EXTRACT_GROUPS('2025-09-10', r'(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})') AS result

/*----------------------------------------------+
 | result                                       |
 +----------------------------------------------+
 | {2025 year, 09 month, 10 day}                |
 +----------------------------------------------*/

Expand STRUCT fields into columns

Because REGEXP_EXTRACT_GROUPS returns a STRUCT, you can use the .* operator in the SELECT list to expand the fields of the STRUCT into separate columns. Expanding STRUCT fields into columns is particularly useful when all capturing groups are named.

SELECT REGEXP_EXTRACT_GROUPS('PROD-WIDGET-1234', r'(?<env>\w+)-(?<product>\w+)-(?<id>\d+)').*

/*-------+-----------+------+
 | env   | product   | id   |
 +-------+-----------+------+
 | PROD  | WIDGET    | 1234 |
 +-------+-----------+------*/

Mix of named and unnamed groups:

SELECT REGEXP_EXTRACT_GROUPS('id:123', r'(?<key>[a-z]+):([0-9]+)') AS result

/*-----------------------+
 | result                |
 +-----------------------+
 | {id key, 123}         |
 +-----------------------*/

No match returns NULL:

SELECT REGEXP_EXTRACT_GROUPS('abc', r'(\d+)') AS result

/*--------+
 | result |
 +--------+
 | NULL   |
 +--------*/

Optional groups and empty matches:

WITH inputs AS (
  SELECT 'id:123:extra' AS t UNION ALL
  SELECT 'id:123:' AS t UNION ALL
  SELECT 'id:123' AS t
)
SELECT
  t,
  REGEXP_EXTRACT_GROUPS(t, r'(?<key>\w+):(?<val>\w+)(?::(?<opt>\w*))?') AS result
FROM inputs;

/*-----------------+--------------------------------------+
 | t               | result                               |
 +-----------------+--------------------------------------+
 | id:123:extra    | {id key, 123 val, extra opt}         |
 | id:123:         | {id key, 123 val,  opt}              |
 | id:123          | {id key, 123 val, NULL opt}          |
 +-----------------+--------------------------------------*/

Note that in the second row, the optional group opt matches an empty string, which is different from the third row where the group doesn't match at all and results in NULL.

Nested groups:

SELECT REGEXP_EXTRACT_GROUPS('a=b=c', r'(\w+)=((\w+)=\w+)') AS result

/*-----------------------+
 | result                |
 +-----------------------+
 | {a, b=c, b}           |
 +-----------------------*/

Alternation with different groups:

WITH inputs AS (
  SELECT 'config_id=123' AS t UNION ALL
  SELECT 'option_name=ABC' AS t
)
SELECT
  t,
  REGEXP_EXTRACT_GROUPS(t, r'config_id=(?<id>\d+)|option_name=(?<name>\w+)') AS result
FROM inputs;

/*-----------------+--------------------------+
 | t               | result                   |
 +-----------------+--------------------------+
 | config_id=123   | {123 id, NULL name}      |
 | option_name=ABC | {NULL id, ABC name}      |
 +-----------------+--------------------------*/

The STRUCT result contains fields for all named capturing groups across all alternatives in the regular expression. In each row, only the fields corresponding to the alternative that matched are populated. Other fields are NULL.

Auto-casting

You can automatically cast the captured substring to a specific type by suffixing the capturing group name with a double underscore (__) followed by the type name.

Any type that can be cast from STRING (or BYTES for the BYTES version of the function) is supported. Type names are case-insensitive.

The field name in the resulting STRUCT will have the __TYPE suffix removed.

If the captured substring can't be cast to the specified type, an error is returned. This includes casting an empty string to a numeric or boolean type. If the captured substring is NULL (due to an optional group not matching), the cast result is also NULL.

Examples of auto-casting

SELECT REGEXP_EXTRACT_GROUPS('val=0x1a', r'val=(?<val__INT64>0x[0-9a-fA-F]+)') AS result

/*-------------+
 | result      |
 +-------------+
 | {26 val}    |
 +-------------*/

Auto-casted values in expressions with Pipe syntax:

FROM UNNEST(['02:30:10', '01:02:03']) AS time_str
|> EXTEND REGEXP_EXTRACT_GROUPS(time_str, r'(?<h__INT64>\d{2}):(?<m__INT64>\d{2}):(?<s__INT64>\d{2})').*
|> SELECT time_str, h * 3600 + m * 60 + s AS total_seconds

/*----------+---------------+
 | time_str | total_seconds |
 +----------+---------------+
 | 02:30:10 | 9010          |
 | 01:02:03 | 3723          |
 +----------+---------------*/

Expand auto-casted fields into columns:

SELECT REGEXP_EXTRACT_GROUPS('2025-09-10', r'(?<year__INT64>\d{4})-(?<month__INT64>\d{2})-(?<day__INT64>\d{2})').*

/*--------+---------+-------+
 | year   | month   | day   |
 +--------+---------+-------+
 | 2025   | 9       | 10    |
 +--------+---------+-------*/

Cast failure:

-- Error: Bad INT64 value
SELECT REGEXP_EXTRACT_GROUPS('ID: ABC', r'ID: (?<item_id__INT64>\w+)')

Cast failure with empty string:

-- Error: Bad INT64 value
SELECT REGEXP_EXTRACT_GROUPS('ID: ', r'ID: (?<item_id__INT64>\d*)')

Workaround for empty string cast failure by making the group optional:

SELECT REGEXP_EXTRACT_GROUPS('ID: ', r'ID: (?<item_id__INT64>\d+)?') AS result

/*-----------------+
 | result          |
 +-----------------+
 | {NULL item_id}  |
 +-----------------*/

REGEXP_EXTRACT_ALL

REGEXP_EXTRACT_ALL(value, regexp)

Description

Returns an array of all substrings of value that match the re2 regular expression, regexp. Returns an empty array if there is no match.

If the regular expression contains a capturing group ((...)), and there is a match for that capturing group, that match is added to the results.

The REGEXP_EXTRACT_ALL function only returns non-overlapping matches. For example, using this function to extract ana from banana returns only one substring, not two.

Returns an error if:

• The regular expression is invalid
• The regular expression has more than one capturing group

Return type

ARRAY<STRING> or ARRAY<BYTES>

Examples

SELECT REGEXP_EXTRACT_ALL('Try `func(x)` or `func(y)`', '`(.+?)`') AS example

/*--------------------+
 | example            |
 +--------------------+
 | [func(x), func(y)] |
 +--------------------*/

REGEXP_INSTR

REGEXP_INSTR(source_value, regexp [, position[, occurrence, [occurrence_position]]])

Description

Returns the lowest 1-based position of a regular expression, regexp, in source_value. source_value and regexp must be the same type, either STRING or BYTES.

If position is specified, the search starts at this position in source_value, otherwise it starts at 1, which is the beginning of source_value. position is of type INT64 and must be positive.

If occurrence is specified, the search returns the position of a specific instance of regexp in source_value. If not specified, occurrence defaults to 1 and returns the position of the first occurrence. For occurrence > 1, the function searches for the next, non-overlapping occurrence. occurrence is of type INT64 and must be positive.

You can optionally use occurrence_position to specify where a position in relation to an occurrence starts. Your choices are:

• 0: Returns the start position of occurrence.
• 1: Returns the end position of occurrence + 1. If the end of the occurrence is at the end of source_value , LENGTH(source_value) + 1 is returned.

Returns 0 if:

• No match is found.
• If occurrence is greater than the number of matches found.
• If position is greater than the length of source_value.
• The regular expression is empty.

Returns NULL if:

• position is NULL.
• occurrence is NULL.

Returns an error if:

• position is 0 or negative.
• occurrence is 0 or negative.
• occurrence_position is neither 0 nor 1.
• The regular expression is invalid.
• The regular expression has more than one capturing group.

Return type

INT64

Examples

SELECT
  REGEXP_INSTR('ab@cd-ef',  '@[^-]*') AS instr_a,
  REGEXP_INSTR('ab@d-ef',   '@[^-]*') AS instr_b,
  REGEXP_INSTR('abc@cd-ef', '@[^-]*') AS instr_c,
  REGEXP_INSTR('abc-ef',    '@[^-]*') AS instr_d,

/*---------------------------------------+
 | instr_a | instr_b | instr_c | instr_d |
 +---------------------------------------+
 | 3       | 3       | 4       | 0       |
 +---------------------------------------*/

SELECT
  REGEXP_INSTR('a@cd-ef b@cd-ef', '@[^-]*', 1) AS instr_a,
  REGEXP_INSTR('a@cd-ef b@cd-ef', '@[^-]*', 2) AS instr_b,
  REGEXP_INSTR('a@cd-ef b@cd-ef', '@[^-]*', 3) AS instr_c,
  REGEXP_INSTR('a@cd-ef b@cd-ef', '@[^-]*', 4) AS instr_d,

/*---------------------------------------+
 | instr_a | instr_b | instr_c | instr_d |
 +---------------------------------------+
 | 2       | 2       | 10      | 10      |
 +---------------------------------------*/

SELECT
  REGEXP_INSTR('a@cd-ef b@cd-ef c@cd-ef', '@[^-]*', 1, 1) AS instr_a,
  REGEXP_INSTR('a@cd-ef b@cd-ef c@cd-ef', '@[^-]*', 1, 2) AS instr_b,
  REGEXP_INSTR('a@cd-ef b@cd-ef c@cd-ef', '@[^-]*', 1, 3) AS instr_c

/*-----------------------------+
 | instr_a | instr_b | instr_c |
 +-----------------------------+
 | 2       | 10      | 18      |
 +-----------------------------*/

SELECT
  REGEXP_INSTR('a@cd-ef', '@[^-]*', 1, 1, 0) AS instr_a,
  REGEXP_INSTR('a@cd-ef', '@[^-]*', 1, 1, 1) AS instr_b

/*-------------------+
 | instr_a | instr_b |
 +-------------------+
 | 2       | 5       |
 +-------------------*/

REGEXP_MATCH (Deprecated)

REGEXP_MATCH(value, regexp)

Description

Returns TRUE if value is a full match for the regular expression, regexp.

If the regexp argument is invalid, the function returns an error.

This function is deprecated. When possible, use REGEXP_CONTAINS to find a partial match for a regular expression.

Note: GoogleSQL provides regular expression support using the re2 library; see that documentation for its regular expression syntax.

Return type

BOOL

Examples

WITH email_addresses AS
  (SELECT 'foo@example.com' as email
  UNION ALL
  SELECT 'bar@example.org' as email
  UNION ALL
  SELECT 'notavalidemailaddress' as email)

SELECT
  email,
  REGEXP_MATCH(email,
               r'[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+')
               AS valid_email_address
FROM email_addresses;

/*-----------------------+---------------------+
 | email                 | valid_email_address |
 +-----------------------+---------------------+
 | foo@example.com       | true                |
 | bar@example.org       | true                |
 | notavalidemailaddress | false               |
 +-----------------------+---------------------*/

REGEXP_REPLACE

REGEXP_REPLACE(value, regexp, replacement)

Description

Returns a STRING where all substrings of value that match regular expression regexp are replaced with replacement.

You can use backslashed-escaped digits (\1 to \9) within the replacement argument to insert text matching the corresponding parenthesized group in the regexp pattern. Use \0 to refer to the entire matching text.

To add a backslash in your regular expression, you must first escape it. For example, SELECT REGEXP_REPLACE('abc', 'b(.)', 'X\\1'); returns aXc. You can also use raw strings to remove one layer of escaping, for example SELECT REGEXP_REPLACE('abc', 'b(.)', r'X\1');.

The REGEXP_REPLACE function only replaces non-overlapping matches. For example, replacing ana within banana results in only one replacement, not two.

If the regexp argument isn't a valid regular expression, this function returns an error.

Note: GoogleSQL provides regular expression support using the re2 library; see that documentation for its regular expression syntax.

Return type

STRING or BYTES

Examples

SELECT REGEXP_REPLACE('# Heading', r'^# ([a-zA-Z0-9\s]+$)', '<h1>\\1</h1>') AS html

/*--------------------------+
 | html                     |
 +--------------------------+
 | <h1>Heading</h1>         |
 +--------------------------*/

REGEXP_SUBSTR

REGEXP_SUBSTR(value, regexp[, position[, occurrence]])

Description

Synonym for REGEXP_EXTRACT.

Return type

STRING or BYTES

Examples

WITH example AS
(SELECT 'Hello World Helloo' AS value, 'H?ello+' AS regex, 1 AS position, 1 AS
occurrence
)
SELECT value, regex, position, occurrence, REGEXP_SUBSTR(value, regex,
position, occurrence) AS regexp_value FROM example;

/*--------------------+---------+----------+------------+--------------+
 | value              | regex   | position | occurrence | regexp_value |
 +--------------------+---------+----------+------------+--------------+
 | Hello World Helloo | H?ello+ | 1        | 1          | Hello        |
 +--------------------+---------+----------+------------+--------------*/

REPEAT

REPEAT(original_value, repetitions)

Description

Returns a STRING or BYTES value that consists of original_value, repeated. The repetitions parameter specifies the number of times to repeat original_value. Returns NULL if either original_value or repetitions are NULL.

This function returns an error if the repetitions value is negative.

Return type

STRING or BYTES

Examples

SELECT REPEAT('abc', 3) AS results

/*-----------+
 | results   |
 |-----------|
 | abcabcabc |
 +-----------*/

SELECT REPEAT('abc', NULL) AS results

/*---------+
 | results |
 |---------|
 | NULL    |
 +---------*/

SELECT REPEAT(NULL, 3) AS results

/*---------+
 | results |
 |---------|
 | NULL    |
 +---------*/

REPLACE

REPLACE(original_value, from_pattern, to_pattern)

Description

Replaces all occurrences of from_pattern with to_pattern in original_value. If from_pattern is empty, no replacement is made.

This function supports specifying collation.

Return type

STRING or BYTES

Examples

WITH desserts AS
  (SELECT 'apple pie' as dessert
  UNION ALL
  SELECT 'blackberry pie' as dessert
  UNION ALL
  SELECT 'cherry pie' as dessert)

SELECT
  REPLACE (dessert, 'pie', 'cobbler') as example
FROM desserts;

/*--------------------+
 | example            |
 +--------------------+
 | apple cobbler      |
 | blackberry cobbler |
 | cherry cobbler     |
 +--------------------*/

REVERSE

REVERSE(value)

Description

Returns the reverse of the input STRING or BYTES.

Return type

STRING or BYTES

Examples

SELECT REVERSE('abc') AS results

/*---------+
 | results |
 +---------+
 | cba     |
 +---------*/

SELECT FORMAT('%T', REVERSE(b'1a3')) AS results

/*---------+
 | results |
 +---------+
 | b"3a1"  |
 +---------*/

RIGHT

RIGHT(value, length)

Description

Returns a STRING or BYTES value that consists of the specified number of rightmost characters or bytes from value. The length is an INT64 that specifies the length of the returned value. If value is BYTES, length is the number of rightmost bytes to return. If value is STRING, length is the number of rightmost characters to return.

If length is 0, an empty STRING or BYTES value will be returned. If length is negative, an error will be returned. If length exceeds the number of characters or bytes from value, the original value will be returned.

Return type

STRING or BYTES

Examples

SELECT 'apple' AS example, RIGHT('apple', 3) AS right_example

/*---------+---------------+
 | example | right_example |
 +---------+---------------+
 | apple   | ple           |
 +---------+---------------*/

SELECT b'apple' AS example, RIGHT(b'apple', 3) AS right_example

/*----------------------+---------------+
 | example              | right_example |
 +----------------------+---------------+
 | apple                | ple           |
 +----------------------+---------------*

RPAD

RPAD(original_value, return_length[, pattern])

Description

Returns a STRING or BYTES value that consists of original_value appended with pattern. The return_length parameter is an INT64 that specifies the length of the returned value. If original_value is BYTES, return_length is the number of bytes. If original_value is STRING, return_length is the number of characters.

The default value of pattern is a blank space.

Both original_value and pattern must be the same data type.

If return_length is less than or equal to the original_value length, this function returns the original_value value, truncated to the value of return_length. For example, RPAD('hello world', 7); returns 'hello w'.

If original_value, return_length, or pattern is NULL, this function returns NULL.

This function returns an error if:

• return_length is negative
• pattern is empty

Return type

STRING or BYTES

Examples

SELECT FORMAT('%T', RPAD('c', 5)) AS results

/*---------+
 | results |
 +---------+
 | "c    " |
 +---------*/

SELECT RPAD('b', 5, 'a') AS results

/*---------+
 | results |
 +---------+
 | baaaa   |
 +---------*/

SELECT RPAD('abc', 10, 'ghd') AS results

/*------------+
 | results    |
 +------------+
 | abcghdghdg |
 +------------*/

SELECT RPAD('abc', 2, 'd') AS results

/*---------+
 | results |
 +---------+
 | ab      |
 +---------*/

SELECT FORMAT('%T', RPAD(b'abc', 10, b'ghd')) AS results

/*---------------+
 | results       |
 +---------------+
 | b"abcghdghdg" |
 +---------------*/

RTRIM

RTRIM(value1[, value2])

Description

Identical to TRIM, but only removes trailing characters.

Return type

STRING or BYTES

Examples

SELECT RTRIM('***apple***', '*') AS example

/*-----------+
 | example   |
 +-----------+
 | ***apple  |
 +-----------*/

SELECT RTRIM('applexxz', 'xyz') AS example

/*---------+
 | example |
 +---------+
 | apple   |
 +---------*/

SAFE_CONVERT_BYTES_TO_STRING

SAFE_CONVERT_BYTES_TO_STRING(value)

Description

Converts a sequence of BYTES to a STRING. Any invalid UTF-8 characters are replaced with the Unicode replacement character, U+FFFD.

Return type

STRING

Examples

The following statement returns the Unicode replacement character, �.

SELECT SAFE_CONVERT_BYTES_TO_STRING(b'\xc2') as safe_convert;

SOUNDEX

SOUNDEX(value)

Description

Returns a STRING that represents the Soundex code for value.

SOUNDEX produces a phonetic representation of a string. It indexes words by sound, as pronounced in English. It's typically used to help determine whether two strings, such as the family names Levine and Lavine, or the words to and too, have similar English-language pronunciation.

The result of the SOUNDEX consists of a letter followed by 3 digits. Non-latin characters are ignored. If the remaining string is empty after removing non-Latin characters, an empty STRING is returned.

Return type

STRING

Examples

SELECT 'Ashcraft' AS value, SOUNDEX('Ashcraft') AS soundex

/*----------------------+---------+
 | value                | soundex |
 +----------------------+---------+
 | Ashcraft             | A261    |
 +----------------------+---------*/

SPLIT

SPLIT(value[, delimiter])

Description

Splits a STRING or BYTES value, using a delimiter. The delimiter argument must be a literal character or sequence of characters. You can't split with a regular expression.

For STRING, the default delimiter is the comma ,.

For BYTES, you must specify a delimiter.

Splitting on an empty delimiter produces an array of UTF-8 characters for STRING values, and an array of BYTES for BYTES values.

Splitting an empty STRING returns an ARRAY with a single empty STRING.

This function supports specifying collation.

Return type

ARRAY<STRING> or ARRAY<BYTES>

Examples

WITH letters AS
  (SELECT '' as letter_group
  UNION ALL
  SELECT 'a' as letter_group
  UNION ALL
  SELECT 'b c d' as letter_group)

SELECT SPLIT(letter_group, ' ') as example
FROM letters;

/*----------------------+
 | example              |
 +----------------------+
 | []                   |
 | [a]                  |
 | [b, c, d]            |
 +----------------------*/

SPLIT_SUBSTR

SPLIT_SUBSTR(value, delimiter, start_split[, count])

Description

Returns a substring from an input STRING that's determined by a delimiter, a location that indicates the first split of the substring to return, and the number of splits to include in the returned substring.

The value argument is the supplied STRING value from which a substring is returned.

The delimiter argument is the delimiter used to split the input STRING. It must be a literal character or sequence of characters.

• The delimiter argument can't be a regular expression.
• Delimiter matching is from left to right.
• If the delimiter is a sequence of characters, then two instances of the delimiter in the input string can't overlap. For example, if the delimiter is **, then the delimiters in the string aa***bb***cc are:
  • The first two asterisks after aa.
  • The first two asterisks after bb.

The start_split argument is an integer that specifies the first split of the substring to return.

• If start_split is 1, then the returned substring starts from the first split.
• If start_split is 0 or less than the negative of the number of splits, then start_split is treated as if it's 1 and returns a substring that starts with the first split.
• If start_split is greater than the number of splits, then an empty string is returned.
• If start_split is negative, then the splits are counted from the end of the input string. If start_split is -1, then the last split in the input string is returned.

The optional count argument is an integer that specifies the maximum number of splits to include in the returned substring.

• If count isn't specified, then the substring from the start_split position to the end of the input string is returned.
• If count is 0, an empty string is returned.
• If count is negative, an error is returned.
• If the sum of count plus start_split is greater than the number of splits, then a substring from start_split to the end of the input string is returned.

This function supports specifying collation.

Return type

STRING

Examples

The following example returns an empty string because count is 0:

SELECT SPLIT_SUBSTR("www.abc.xyz.com", ".", 1, 0) AS example

/*---------+
 | example |
 +---------+
 |         |
 +---------*/

The following example returns two splits starting with the first split:

SELECT SPLIT_SUBSTR("www.abc.xyz.com", ".", 1, 2) AS example

/*---------+
 | example |
 +---------+
 | www.abc |
 +---------*/

The following example returns one split starting with the first split:

SELECT SPLIT_SUBSTR("www.abc.xyz.com", ".", 1, 1) AS example

/*---------+
 | example |
 +---------+
 | www     |
 +---------*/

The following example returns splits from the right because start_split is a negative value:

SELECT SPLIT_SUBSTR("www.abc.xyz.com", ".", -1, 1) AS example

/*---------+
 | example |
 +---------+
 | com     |
 +---------*/

The following example returns a substring with three splits, starting with the first split:

SELECT SPLIT_SUBSTR("www.abc.xyz.com", ".", 1, 3) AS example

/*-------------+
 | example     |
 +-------------+
 | www.abc.xyz |
 +------------*/

If start_split is zero, then it's treated as if it's 1. The following example returns three substrings starting with the first split:

SELECT SPLIT_SUBSTR("www.abc.xyz.com", ".", 0, 3) AS example

/*-------------+
 | example     |
 +-------------+
 | www.abc.xyz |
 +------------*/

If start_split is greater than the number of splits, then an empty string is returned:

SELECT SPLIT_SUBSTR("www.abc.xyz.com", ".", 5, 3) AS example

/*---------+
 | example |
 +---------+
 |         |
 +--------*/

In the following example, the start_split value (-5) is less than the negative of the number of splits (-4), so start_split is treated as 1:

SELECT SPLIT_SUBSTR("www.abc.xyz.com", ".", -5, 3) AS example

/*-------------+
 | example     |
 +-------------+
 | www.abc.xyz |
 +------------*/

In the following example, the substring from start_split to the end of the string is returned because count isn't specified:

SELECT SPLIT_SUBSTR("www.abc.xyz.com", ".", 3) AS example

/*---------+
 | example |
 +---------+
 | xyz.com |
 +--------*/

The following two examples demonstrate how SPLIT_SUBSTR works with a multi-character delimiter that has overlapping matches in the input string. In each example, the input string contains instances of three asterisks in a row (***) and the delimiter is two asterisks (**).

SELECT SPLIT_SUBSTR('aaa***bbb***ccc', '**', 1, 2) AS example

/*-----------+
 | example   |
 +-----------+
 | aaa***bbb |
 +----------*/

SELECT SPLIT_SUBSTR('aaa***bbb***ccc', '**', 2, 2) AS example

/*------------+
 | example    |
 +------------+
 | *bbb***ccc |
 +-----------*/

STARTS_WITH

STARTS_WITH(value, prefix)

Description

Takes two STRING or BYTES values. Returns TRUE if prefix is a prefix of value.

This function supports specifying collation.

Return type

BOOL

Examples

SELECT STARTS_WITH('bar', 'b') AS example

/*---------+
 | example |
 +---------+
 |    True |
 +---------*/

STRPOS

STRPOS(value, subvalue)

Description

Takes two STRING or BYTES values. Returns the 1-based position of the first occurrence of subvalue inside value. Returns 0 if subvalue isn't found.

This function supports specifying collation.

Return type

INT64

Examples

SELECT STRPOS('foo@example.com', '@') AS example

/*---------+
 | example |
 +---------+
 |       4 |
 +---------*/

SUBSTR

SUBSTR(value, position[, length])

Description

Gets a portion (substring) of the supplied STRING or BYTES value.

The position argument is an integer specifying the starting position of the substring.

• If position is 1, the substring starts from the first character or byte.
• If position is 0 or less than -LENGTH(value), position is set to 1, and the substring starts from the first character or byte.
• If position is greater than the length of value, the function produces an empty substring.
• If position is negative, the function counts from the end of value, with -1 indicating the last character or byte.

The length argument specifies the maximum number of characters or bytes to return.

• If length isn't specified, the function produces a substring that starts at the specified position and ends at the last character or byte of value.
• If length is 0, the function produces an empty substring.
• If length is negative, the function produces an error.
• The returned substring may be shorter than length, for example, when length exceeds the length of value, or when the starting position of the substring plus length is greater than the length of value.

Return type

STRING or BYTES

Examples

SELECT SUBSTR('apple', 2) AS example

/*---------+
 | example |
 +---------+
 | pple    |
 +---------*/

SELECT SUBSTR('apple', 2, 2) AS example

/*---------+
 | example |
 +---------+
 | pp      |
 +---------*/

SELECT SUBSTR('apple', -2) AS example

/*---------+
 | example |
 +---------+
 | le      |
 +---------*/

SELECT SUBSTR('apple', 1, 123) AS example

/*---------+
 | example |
 +---------+
 | apple   |
 +---------*/

SELECT SUBSTR('apple', 123) AS example

/*---------+
 | example |
 +---------+
 |         |
 +---------*/

SELECT SUBSTR('apple', 123, 5) AS example

/*---------+
 | example |
 +---------+
 |         |
 +---------*/

SUBSTRING

SUBSTRING(value, position[, length])

Alias for SUBSTR.

TO_BASE32

TO_BASE32(bytes_expr)

Description

Converts a sequence of BYTES into a base32-encoded STRING. To convert a base32-encoded STRING into BYTES, use FROM_BASE32.

Return type

STRING

Example

SELECT TO_BASE32(b'abcde\xFF') AS base32_string;

/*------------------+
 | base32_string    |
 +------------------+
 | MFRGGZDF74====== |
 +------------------*/

TO_BASE64

TO_BASE64(bytes_expr)

Description

Converts a sequence of BYTES into a base64-encoded STRING. To convert a base64-encoded STRING into BYTES, use FROM_BASE64.

There are several base64 encodings in common use that vary in exactly which alphabet of 65 ASCII characters are used to encode the 64 digits and padding. See RFC 4648 for details. This function adds padding and uses the alphabet [A-Za-z0-9+/=].

Return type

STRING

Example

SELECT TO_BASE64(b'\377\340') AS base64_string;

/*---------------+
 | base64_string |
 +---------------+
 | /+A=          |
 +---------------*/

To work with an encoding using a different base64 alphabet, you might need to compose TO_BASE64 with the REPLACE function. For instance, the base64url url-safe and filename-safe encoding commonly used in web programming uses -_= as the last characters rather than +/=. To encode a base64url-encoded string, replace + and / with - and _ respectively.

SELECT REPLACE(REPLACE(TO_BASE64(b'\377\340'), '+', '-'), '/', '_') as websafe_base64;

/*----------------+
 | websafe_base64 |
 +----------------+
 | _-A=           |
 +----------------*/

TO_CODE_POINTS

TO_CODE_POINTS(value)

Description

Takes a STRING or BYTES value and returns an array of INT64 values that represent code points or extended ASCII character values.

• If value is a STRING, each element in the returned array represents a code point. Each code point falls within the range of [0, 0xD7FF] and [0xE000, 0x10FFFF].
• If value is BYTES, each element in the array is an extended ASCII character value in the range of [0, 255].

To convert from an array of code points to a STRING or BYTES, see CODE_POINTS_TO_STRING or CODE_POINTS_TO_BYTES.

Return type

ARRAY<INT64>

Examples

The following examples get the code points for each element in an array of words.

SELECT
  'foo' AS word,
  TO_CODE_POINTS('foo') AS code_points

/*---------+------------------------------------+
 | word    | code_points                        |
 +---------+------------------------------------+
 | foo     | [102, 111, 111]                    |
 +---------+------------------------------------*/

SELECT
  'bar' AS word,
  TO_CODE_POINTS('bar') AS code_points

/*---------+------------------------------------+
 | word    | code_points                        |
 +---------+------------------------------------+
 | bar     | [98, 97, 114]                      |
 +---------+------------------------------------*/

SELECT
  'baz' AS word,
  TO_CODE_POINTS('baz') AS code_points

/*---------+------------------------------------+
 | word    | code_points                        |
 +---------+------------------------------------+
 | baz     | [98, 97, 122]                      |
 +---------+------------------------------------*/

SELECT
  'giraffe' AS word,
  TO_CODE_POINTS('giraffe') AS code_points

/*---------+------------------------------------+
 | word    | code_points                        |
 +---------+------------------------------------+
 | giraffe | [103, 105, 114, 97, 102, 102, 101] |
 +---------+------------------------------------*/

SELECT
  'llama' AS word,
  TO_CODE_POINTS('llama') AS code_points

/*---------+------------------------------------+
 | word    | code_points                        |
 +---------+------------------------------------+
 | llama   | [108, 108, 97, 109, 97]            |
 +---------+------------------------------------*/

The following examples convert integer representations of BYTES to their corresponding ASCII character values.

SELECT
  b'\x66\x6f\x6f' AS bytes_value,
  TO_CODE_POINTS(b'\x66\x6f\x6f') AS bytes_value_as_integer

/*------------------+------------------------+
 | bytes_value      | bytes_value_as_integer |
 +------------------+------------------------+
 | foo              | [102, 111, 111]        |
 +------------------+------------------------*/

SELECT
  b'\x00\x01\x10\xff' AS bytes_value,
  TO_CODE_POINTS(b'\x00\x01\x10\xff') AS bytes_value_as_integer

/*------------------+------------------------+
 | bytes_value      | bytes_value_as_integer |
 +------------------+------------------------+
 | \x00\x01\x10\xff | [0, 1, 16, 255]        |
 +------------------+------------------------*/

The following example demonstrates the difference between a BYTES result and a STRING result. Notice that the character Ā is represented as a two-byte Unicode sequence. As a result, the BYTES version of TO_CODE_POINTS returns an array with two elements, while the STRING version returns an array with a single element.

SELECT TO_CODE_POINTS(b'Ā') AS b_result, TO_CODE_POINTS('Ā') AS s_result;

/*------------+----------+
 | b_result   | s_result |
 +------------+----------+
 | [196, 128] | [256]    |
 +------------+----------*/

TO_HEX

TO_HEX(bytes)

Description

Converts a sequence of BYTES into a hexadecimal STRING. Converts each byte in the STRING as two hexadecimal characters in the range (0..9, a..f). To convert a hexadecimal-encoded STRING to BYTES, use FROM_HEX.

Return type

STRING

Example

SELECT
  b'\x00\x01\x02\x03\xAA\xEE\xEF\xFF' AS byte_string,
  TO_HEX(b'\x00\x01\x02\x03\xAA\xEE\xEF\xFF') AS hex_string

/*----------------------------------+------------------+
 | byte_string                      | hex_string       |
 +----------------------------------+------------------+
 | \x00\x01\x02\x03\xaa\xee\xef\xff | 00010203aaeeefff |
 +----------------------------------+------------------*/

TRANSLATE

TRANSLATE(expression, source_characters, target_characters)

Description

In expression, replaces each character in source_characters with the corresponding character in target_characters. All inputs must be the same type, either STRING or BYTES.

• Each character in expression is translated at most once.
• A character in expression that isn't present in source_characters is left unchanged in expression.
• A character in source_characters without a corresponding character in target_characters is omitted from the result.
• A duplicate character in source_characters results in an error.

Return type

STRING or BYTES

Examples

SELECT TRANSLATE('This is a cookie', 'sco', 'zku') AS translate

/*------------------+
 | translate        |
 +------------------+
 | Thiz iz a kuukie |
 +------------------*/

TRIM

TRIM(value_to_trim[, set_of_characters_to_remove])

Description

Takes a STRING or BYTES value to trim.

If the value to trim is a STRING, removes from this value all leading and trailing Unicode code points in set_of_characters_to_remove. The set of code points is optional. If it isn't specified, all whitespace characters are removed from the beginning and end of the value to trim.

If the value to trim is BYTES, removes from this value all leading and trailing bytes in set_of_characters_to_remove. The set of bytes is required.

Return type

• STRING if value_to_trim is a STRING value.
• BYTES if value_to_trim is a BYTES value.

Examples

In the following example, all leading and trailing whitespace characters are removed from item because set_of_characters_to_remove isn't specified.

SELECT CONCAT('#', TRIM( '   apple   '), '#') AS example

/*----------+
 | example  |
 +----------+
 | #apple#  |
 +----------*/

In the following example, all leading and trailing * characters are removed from 'apple'.

SELECT TRIM('***apple***', '*') AS example

/*---------+
 | example |
 +---------+
 | apple   |
 +---------*/

In the following example, all leading and trailing x, y, and z characters are removed from 'xzxapplexxy'.

SELECT TRIM('xzxapplexxy', 'xyz') as example

/*---------+
 | example |
 +---------+
 | apple   |
 +---------*/

In the following example, examine how TRIM interprets characters as Unicode code-points. If your trailing character set contains a combining diacritic mark over a particular letter, TRIM might strip the same diacritic mark from a different letter.

SELECT
  TRIM('abaW̊', 'Y̊') AS a,
  TRIM('W̊aba', 'Y̊') AS b,
  TRIM('abaŪ̊', 'Y̊') AS c,
  TRIM('Ū̊aba', 'Y̊') AS d

/*------+------+------+------+
 | a    | b    | c    | d    |
 +------+------+------+------+
 | abaW | W̊aba | abaŪ | Ūaba |
 +------+------+------+------*/

In the following example, all leading and trailing b'n', b'a', b'\xab' bytes are removed from item.

SELECT b'apple', TRIM(b'apple', b'na\xab') AS example

/*----------------------+------------------+
 | item                 | example          |
 +----------------------+------------------+
 | apple                | pple             |
 +----------------------+------------------*/

UNICODE

UNICODE(value)

Description

Returns the Unicode code point for the first character in value. Returns 0 if value is empty, or if the resulting Unicode code point is 0.

Return type

INT64

Examples

SELECT UNICODE('âbcd') as A, UNICODE('â') as B, UNICODE('') as C, UNICODE(NULL) as D;

/*-------+-------+-------+-------+
 | A     | B     | C     | D     |
 +-------+-------+-------+-------+
 | 226   | 226   | 0     | NULL  |
 +-------+-------+-------+-------*/

UPPER

UPPER(value)

Description

For STRING arguments, returns the original string with all alphabetic characters in uppercase. Mapping between uppercase and lowercase is done according to the Unicode Character Database without taking into account language-specific mappings.

For BYTES arguments, the argument is treated as ASCII text, with all bytes greater than 127 left intact.

Return type

STRING or BYTES

Examples

SELECT UPPER('foo') AS example

/*---------+
 | example |
 +---------+
 | FOO     |
 +---------*/