diff --git a/lib/private/DB/QueryBuilder/QueryBuilder.php b/lib/private/DB/QueryBuilder/QueryBuilder.php
index 3cb7ba133db35b18ad18f160384df3504e495141..ebbcdeb0870d0ae2c2ad13d3144ffc990eadd6e6 100644
--- a/lib/private/DB/QueryBuilder/QueryBuilder.php
+++ b/lib/private/DB/QueryBuilder/QueryBuilder.php
@@ -813,7 +813,7 @@ class QueryBuilder implements IQueryBuilder {
 	 */
 	public function groupBy(...$groupBys) {
 		if (count($groupBys) === 1 && is_array($groupBys[0])) {
-			$$groupBys = $groupBys[0];
+			$groupBys = $groupBys[0];
 		}
 
 		call_user_func_array(