Select spec for https://github.com/Happyr/Doctrine-Specification

Select.php

<?php

namespace AppBundle\Entity\Spec;

use Doctrine\ORM\QueryBuilder;
use Happyr\DoctrineSpecification\Query\QueryModifier;

/**
 * Class Select
 */
class Select implements QueryModifier
{
    /**
     * @var string field
     */
    protected $alias;

    /**
     * @param string $alias
     */
    public function __construct($alias)
    {
        $this->alias = $alias;
    }

    /**
     * @param QueryBuilder $qb
     * @param string       $dqlAlias
     */
    public function modify(QueryBuilder $qb, $dqlAlias)
    {
        $qb->addSelect($this->alias);
    }
}

Use

return Spec::andX(
    new Select('MIN(variants.price) AS price')
);

variants - alias