eZ\Publish\Core\Persistence\Doctrine\DoctrineExpression::isNull PHP Method

Example:


$q = $dbHandler->createSelectQuery();
$q->select( '*' )->from( 'table' )
                 ->where( $q->expr->isNull( 'id' ) );

public isNull ( string $expression ) : string
$expression	string	the expression that should be compared to null
return	string	logical expression

    public function isNull($expression)
    {
        return "{$expression} IS NULL";
    }

DoctrineExpression