how to concat join by qb in doctrine? - doctrine

Question

I want to add a join to my query in if condition but it returned an error.
how we can do it in doctrine?
is there any thing like:
$qb->andWhere('p.$gender = :g')->setParameter('g', $gender);
for join in doctrine symfony??
$qb->select("p")->from("PfmSanadBundle:Person", "p");
if ((isset($province) && trim($province) !== '') && (isset($City) && trim($City) !== '')){
$qb->join("p" ,"students", "ps")
->join("ps" ,"organization", "po")
->join("po" ,"cityProvince", "pc")
->join("pc" ,"province", "pp");
}
if ((isset($province) && trim($province) !== '') && !isset($City)) {
$qb->join("p.students", "ps")
->join("ps.organization", "po");
}
$res = $qb->getQuery()->getArrayResult();
error (postman):
"error": {
"code": 500,
"message": "Internal Server Error",
"exception": [
{
"message": "[Semantical Error] line 0, col 49 near 'p students INNER': Error: Class 'p' is not defined.",
"class": "Doctrine\ORM\Query\QueryException",
"trace": [
{

Answer 1

Join method usage is following
// Example - $qb->join('u.Group', 'g', Expr\Join::WITH, $qb->expr()->eq('u.status_id', '?1'))
// Example - $qb->join('u.Group', 'g', 'WITH', 'u.status = ?1')
// Example - $qb->join('u.Group', 'g', 'WITH', 'u.status = ?1', 'g.id')
public function join($join, $alias, $conditionType = null, $condition = null, $indexBy = null);
Thus following lines
$qb->join("p" ,"students", "ps")
->join("ps" ,"organization", "po")
->join("po" ,"cityProvince", "pc")
->join("pc" ,"province", "pp");
change to
$qb->join("p.students", "ps")
->join("ps.organization", "po")
->join("po.cityProvince", "pc")
->join("pc.province", "pp");