symfony2: how to use group_concat in QueryBuilder - symfony

Question

I am having nested-set (using Gedmo tree) entity called "Location". Entity "Appartment" has location_id and what I need to do it to map scalar value called eg "path" to query that returns all appartments.
In Doctrine1, I had this code:
/**
* Add "path" to each element
*
* #param Doctrine_Query $query
* #param string $separator
*/
protected function addScalar_path(Doctrine_Query $query, $separator=", ")
{
$subquery = "k99.root_id=o.root_id AND k99.lft<=o.lft AND k99.rgt>=o.rgt AND k99.level<=o.level" ;
$query->addSelect("(SELECT GROUP_CONCAT(k99.name ORDER BY k99.level SEPARATOR '$separator') FROM Location k99 WHERE $subquery) AS path") ;
}
Note: "o" alias is used for primary query.
This code would allow me to use
{foreach .... as $appartment}
{$appartment->path}
...
Which would print:
Australia, Victoria, Melbourne, ...other children...
How to do the same thing in D2? And how to even include doctrine extenstions in my symfony2 project?

Answer 1

If you want to use it in QueryBuilder you must :
1) add DQL functions GroupConcat: GroupConcat
2 ) Registering GroupConcat :DQL User Defined Functions
another alternative is to use NativeQuery :Native SQL
In symfony2 registering a function DQL it's very simple just add GROUP_CONCAT in config.yml like:
entity_managers:
default:
dql:
string_functions:
GROUP_CONCAT: YourBundle\Query\Mysql\GroupConcat
For more information visit Registering Custom DQL Functions

Answer 2

If any comes across this post, there's now a Doctrine Extensions repository in Github. The repo has instructions on how to use it. You can use composer to install it and then use any function you're interested in.
EDIT:
For the Sake of the user Tushar, the way to use GROUP_CONCAT in Doctrine2's DQL is simple install Doctrine Extensions:
composer require beberlei/DoctrineExtensions
To enable it: add the following in your config.yml:
doctrine:
orm:
dql:
string_functions:
group_concat: DoctrineExtensions\Query\Mysql\GroupConcat
Then in your code, you should be able now to use Group Concat in your DQLs:
$this->createQueryBuilder('location')
->select('location')
->addSelect("GROUP_CONCAT(DISTINCT location.name SEPARATOR '; ') AS locationNames");
$result = $queryBuilder->getQuery()->getResult();
Or in the case for the original question:
$query->addSelect("(SELECT GROUP_CONCAT(k99.name ORDER BY k99.level SEPARATOR '$separator') FROM Location k99 WHERE $subquery) AS path");

Answer 3

Just an addition to #a.aitboudad's answer: The DQL function GroupConcat linked appears to have a «limited support for GROUP_CONCAT».
Here is the full support version :
The configuration is as he mentioned.
// -------------------------------------------------
// 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();

Answer 4

I had similar problem. GROUP_CONCAT does not allow using CASE-WHEN inside.
This library fixed my issues, so maybe it will be helpful.