How to select randomly with doctrine

The Doctrine team is not willing to implement this feature.

There are several solutions to your problem, each having its own drawbacks:

• Add a custom numeric function: see this DQL RAND() function
  (might be slow if you have lots of matching rows)
• Use a native query
  (I personally try to avoid this solution, which I found hard to maintain)
• Issue a raw SQL query first to get some IDs randomly, then use the DQL WHERE x.id IN(?) to load the associated objects, by passing the array of IDs as a parameter.
  This solution involves two separate queries, but might give better performance than the first solution (other raw SQL techniques than ORDER BY RAND() exist, I won't detail them here, you'll find some good resources on this website).

Follow these steps:

Define a new class at your project as:

namespace My\Custom\Doctrine2\Function;

use Doctrine\ORM\Query\Lexer;

class Rand extends \Doctrine\ORM\Query\AST\Functions\FunctionNode
{

    public function parse(\Doctrine\ORM\Query\Parser $parser)
    {
        $parser->match(Lexer::T_IDENTIFIER);
        $parser->match(Lexer::T_OPEN_PARENTHESIS);
        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
    }

    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
    {
        return 'RAND()';
    }
}

Register the class config.yml:

doctrine:
     orm:
         dql:
             numeric_functions:
                 Rand: My\Custom\Doctrine2\Function\Rand

Use it directly as:

$qb->addSelect('RAND() as HIDDEN rand')->orderBy('rand()'); //Missing curly brackets