SET a variable into DQL query - php

Question

I want to set a variable into a DQL query on the basis of condition
case when both varibale value are matches the set variable rank.
dql query
$q=$this->em->createQuery("select distinct u.id,u.city,u.country,u.designation FROM Entities\User u JOIN Entities\EventVisitor evt_vstr WITH evt_vstr.user = u.id WHERE (
CASE
WHEN $a =u.designation THEN SET #rank=1
WHEN $b =u.country THEN SET #rank=2
WHEN $c =u.city THEN SET #rank=3
WHEN $d =u.company THEN #rank=4
END) order by #rank")
->setFirstResult($i)
->setMaxResults($max_result);
$results = $q->getResult();
Here rank is the variable i am trying to set
problem im facing
im unable to set variable in dql .
errorlog
PHP Fatal error: Uncaught exception 'Doctrine\\ORM\\Query\\QueryException' with message 'select distinct u.id, u.city,u.country,u.designation FROM Entities\\User u JOIN Entities\\EventVisitor evt_vstr WITH evt_vstr.user = u.id \n\t \t\t\t\t\tWHERE (\n\t\t\t\t\t\t\t\t\tCASE\n\t\t\t\t\t\t\t\t\t\t\t\tWHEN Co-founder =u.designation THEN SET #rank=1\n\t\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\tEND ) ' in /home/india/public_html/serve-trade-com/application/libraries/Doctrine/ORM/Query/QueryException.php:39\nStack
But its not working.
How can i do that ?
OR is there any way to do that
Please help

Answer 1

Unfortunately I don't think that's possible in DQL, but you can use just plain SQL with Doctrine. take a look at the createNativeQuery function.
If you want to use it with an Symfony2 Entity, you should also take a look at the Doctrine\ORM\Query\ResultSetMapping class, which is used to create proper Entities out of the result.
Hope this helps.
Btw. In my opinion you shouldn't use PHP variables in your DQL string, but instead work with parameters, you can read about them here.