Expression

API reference › yii › db › Expression

class	`yii\db\Expression`
Extends	`yii\base\BaseObject`
Implements	`ExpressionInterface`, `yii\base\Configurable`
Since	2.0
Source	`framework/db/Expression.php`

Expression represents a DB expression that does not need escaping or quoting.

When an Expression object is embedded within a SQL statement or fragment, it will be replaced with the $expression property value without any DB escaping or quoting. For example,

$expression = new Expression('NOW()');
$now = (new \yii\db\Query)->select($expression)->scalar();  // SELECT NOW();
echo $now; // prints the current date

Expression objects are mainly created for passing raw SQL expressions to methods of Query, ActiveQuery, and related classes.

An expression can also be bound with parameters specified via $params.

Properties

Property	Type	Description	Defined by
`$expression`	`string`	The DB expression Default: `null`.	`Expression`
`$params`	`array`	List of parameters that should be bound for this expression. Default: `[]`.	`Expression`

Methods

Method	Description	Defined by
`__construct()`	Constructor.	`Expression`
`__call()`	Calls the named method which is not a class method.	`yii\base\BaseObject`
`__get()`	Returns the value of an object property.	`yii\base\BaseObject`
`__isset()`	Checks if a property is set, i.e. defined and not null.	`yii\base\BaseObject`
`__set()`	Sets value of an object property.	`yii\base\BaseObject`
`__toString()`	String magic method.	`Expression`
`__unset()`	Sets an object property to null.	`yii\base\BaseObject`
`canGetProperty()`	Returns a value indicating whether a property can be read.	`yii\base\BaseObject`
`canSetProperty()`	Returns a value indicating whether a property can be set.	`yii\base\BaseObject`
`className()` static	Returns the fully qualified name of this class.	`yii\base\BaseObject`
`hasMethod()`	Returns a value indicating whether a method is defined.	`yii\base\BaseObject`
`hasProperty()`	Returns a value indicating whether a property is defined.	`yii\base\BaseObject`
`init()`	Initializes the object.	`yii\base\BaseObject`

Property details

$params

public array $params = []

List of parameters that should be bound for this expression.

The keys are placeholders appearing in $expression and the values are the corresponding parameter values.

Method details

__construct()

public function __construct(string $expression, array $params = [], array $config = [])

Constructor.

Parameters

Parameter	Type	Description
`$expression`	`string`	The DB expression
`$params`	`array`	Parameters
`$config`	`array`	Name-value pairs that will be used to initialize the object properties

__toString()

public function __toString(): string

String magic method.

Returns

string: The DB expression.