Expression

The Yiisoft\Db\Expression\Expression class represents a DB expression that does not require escaping or quoting of its content. It is useful when you need to include database functions, operators, or other SQL constructs that cannot be represented by the query builder's methods.

use Yiisoft\Db\Expression\Expression;

new Expression('NOW()');
new Expression('[[column1]] + [[column2]]');

It allows you to specify a raw SQL expression that will be included in the generated SQL statement as is.

Parameters

When using parameters in an expression, you can provide them as an associative array where the keys are the parameter names and the values are the corresponding values to be bound.

new Expression('[[column]] = :value', [':value' => 123]);

Nested expressions

You can also nest other expressions via parameters. For example:

new Expression('[[column]] = :value', [':value' => new Expression('NOW()')]);

This will generate the following SQL:

"column" = NOW()

Usage

The following example shows how to use the Expression class in a query:

/** @var Yiisoft\Db\Connection\ConnectionInterface $db */
$rows = $db->select(['id', 'created_at' => new Expression('NOW()')])
    ->from('{{%user}}')
    ->where(new Expression('[[status]] = :status', [':status' => 1]))
    ->all();

The above code generates and executes the following SQL query:

SELECT "id", NOW() AS "created_at" FROM "user" WHERE "status" = :status