doctrine2 and group_concat

Question

i've been looking through the docs/google and didn't find any solution.

is there any way to execute or imitate GROUP_CONCAT using doctrine2 (DQL) without native mysql?

eg.:

SELECT u.id, u.name, [GROUP_CONCAT(...)] AS user_messages
FROM models\Users u
LEFT JOIN models\Messages m
GROUP BY u.id

to get

GROUP_CONCAT(m.id,'|',m.title SEPARATOR ':')

right now i'm using the createNativeQuery() to run it, but i'm looking for a doctrine2 solution.

thanks in advance

Answer 1

Yes this is possible with DoctrineExtensions from Beberlei (a core developer of Doctrine2). In doctrine2 you can define your own query expressions by extending the functionNode class.

The easiest way is to include the DoctrineExtensions lib in your project. I don't know wether your are using Zend Framework or Symfony or any other framework so can't help you with embedding it.

You can checkout DoctrineExtensions here:

https://github.com/beberlei/DoctrineExtensions

And the group function:

https://github.com/beberlei/DoctrineExtensions/blob/master/src/Query/Mysql/GroupConcat.php

Be aware you should use GroupConcat as function name not GROUP_CONCAT like in MySQL.

Hope it helps you!

Answer 2

Here is the full support version :

// -------------------------------------------------
// Complete support of GROUP_CONCAT in Doctrine2
// -------------------------------------------------
// Original Article: http://habrahabr.ru/post/181666/
// Automated translation to English: http://sysmagazine.com/posts/181666/ 
// Original github commit: https://github.com/denisvmedia/DoctrineExtensions/blob/d1caf21cd7c71cc557e60c26e9bf25323a194dd1/lib/DoctrineExtensions/Query/Mysql/GroupConcat.php

/**
 * DoctrineExtensions Mysql Function Pack
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to kontakt@beberlei.de so I can send you a copy immediately.
 */

namespace DoctrineExtensions\Query\Mysql;

use Doctrine\ORM\Query\AST\Functions\FunctionNode,
    Doctrine\ORM\Query\Lexer;

/**
 * Full support for:
 *
 * GROUP_CONCAT([DISTINCT] expr [,expr ...]
 *              [ORDER BY {unsigned_integer | col_name | expr}
 *                  [ASC | DESC] [,col_name ...]]
 *              [SEPARATOR str_val])
 *
 */
class GroupConcat extends FunctionNode
{
    public $isDistinct = false;
    public $pathExp = null;
    public $separator = null;
    public $orderBy = null;

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

        $lexer = $parser->getLexer();
        if ($lexer->isNextToken(Lexer::T_DISTINCT)) {
            $parser->match(Lexer::T_DISTINCT);

            $this->isDistinct = true;
        }

        // first Path Expression is mandatory
        $this->pathExp = array();
        $this->pathExp[] = $parser->SingleValuedPathExpression();

        while ($lexer->isNextToken(Lexer::T_COMMA)) {
            $parser->match(Lexer::T_COMMA);
            $this->pathExp[] = $parser->StringPrimary();
        }

        if ($lexer->isNextToken(Lexer::T_ORDER)) {
            $this->orderBy = $parser->OrderByClause();
        }

        if ($lexer->isNextToken(Lexer::T_IDENTIFIER)) {
            if (strtolower($lexer->lookahead['value']) !== 'separator') {
                $parser->syntaxError('separator');
            }
            $parser->match(Lexer::T_IDENTIFIER);

            $this->separator = $parser->StringPrimary();
        }

        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
    }

    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
    {
        $result = 'GROUP_CONCAT(' . ($this->isDistinct ? 'DISTINCT ' : '');

        $fields = array();
        foreach ($this->pathExp as $pathExp) {
            $fields[] = $pathExp->dispatch($sqlWalker);
        }

        $result .= sprintf('%s', implode(', ', $fields));

        if ($this->orderBy) {
            $result .= ' ' . $sqlWalker->walkOrderByClause($this->orderBy);
        }

        if ($this->separator) {
            $result .= ' SEPARATOR ' . $sqlWalker->walkStringPrimary($this->separator);
        }

        $result .= ')';

        return $result;
    }

}

// -------------------------------------------------
// Example of usage:
// -------------------------------------------------
$query = $this->createQueryBuilder('c')
    ->select("
            c as company,
            GroupConcat(b.id, ';', b.headOffice, ';', b.city, ';', s.name
            ORDER by b.id
            SEPARATOR '|') AS branches
        ")->leftJoin('c.branches', 'b')
    ->leftJoin('b.country', 's')
    ->groupBy('c.id')
    ->setFirstResult(0)
    ->setMaxResults(10)
    ->getQuery();
$result = $query->getResult();