diff --git a/lib/Db/RoomMapper.php b/lib/Db/RoomMapper.php
index cac261e..49948bc 100644
--- a/lib/Db/RoomMapper.php
+++ b/lib/Db/RoomMapper.php
@@ -22,7 +22,7 @@ class RoomMapper extends QBMapper {
 		$qb->select('r.*')
 			->from($this->tableName, 'r')
 			->leftJoin('r', 'bbb_room_shares', 's', $qb->expr()->eq('r.id', 's.room_id'))
-			->addSelect($qb->createFunction('count(case when "s"."permission" = 0 then 1 else null end) as shared'))
+			->addSelect($qb->createFunction('count(case when `s`.`permission` = 0 then 1 else null end) as shared'))
 			->where($qb->expr()->eq('r.id', $qb->createNamedParameter($id, IQueryBuilder::PARAM_INT)))
 			->groupBy('r.id');
 		;
@@ -41,7 +41,7 @@ class RoomMapper extends QBMapper {
 		$qb->select('r.*')
 			->from($this->tableName, 'r')
 			->leftJoin('r', 'bbb_room_shares', 's', $qb->expr()->eq('r.id', 's.room_id'))
-			->addSelect($qb->createFunction('count(case when "s"."permission" = 0 then 1 else null end) as shared'))
+			->addSelect($qb->createFunction('count(case when `s`.`permission` = 0 then 1 else null end) as shared'))
 			->where($qb->expr()->eq('r.uid', $qb->createNamedParameter($uid)))
 			->groupBy('r.id');
 		;
@@ -59,7 +59,7 @@ class RoomMapper extends QBMapper {
 		$qb->select('r.*')
 			->from($this->tableName, 'r')
 			->leftJoin('r', 'bbb_room_shares', 's', $qb->expr()->eq('r.id', 's.room_id'))
-			->addSelect($qb->createFunction('count(case when "s"."permission" = 0 then 1 else null end) as shared'))
+			->addSelect($qb->createFunction('count(case when `s`.`permission` = 0 then 1 else null end) as shared'))
 			->where(
 				$qb->expr()->orX(
 					$qb->expr()->eq('r.user_id', $qb->createNamedParameter($userId)),