Fix PostgresQL test (a stab in the dark)

Author: mpdude

tests/Doctrine/Tests/ORM/Functional/Ticket/GH5998Test.php

@@ -55,7 +55,7 @@ private function classTests($className): void
         $this->_em->clear();
 
         // Test query by id with fetch join
-        $child = $this->_em->createQuery('SELECT t, r FROM ' . $className . ' t JOIN t.rel r WHERE t.id = 1')->getOneOrNullResult();
+        $child = $this->_em->createQuery('SELECT t, r FROM ' . $className . ' t JOIN t.rel r WHERE t.id = ?0')->setParameter(0, $child->id)->getOneOrNullResult();
         self::assertNotNull($child);
 
         // Test lock and update