diff --git a/src/NetteDatabaseDataSource.php b/src/NetteDatabaseDataSource.php
index e64464d..36cb84d 100644
--- a/src/NetteDatabaseDataSource.php
+++ b/src/NetteDatabaseDataSource.php
@@ -226,17 +226,14 @@ public function limit(int $offset, int $limit): IDataSource
 	public function sort(Sorting $sorting): IDataSource
 	{
 		if (is_callable($sorting->getSortCallback())) {
-			call_user_func(
+			$sort = call_user_func(
 				$sorting->getSortCallback(),
-				$this->sql,
 				$sorting->getSort()
 			);
-
-			return $this;
+		} else {
+			$sort = $sorting->getSort();
 		}
 
-		$sort = $sorting->getSort();
-
 		if ($sort !== []) {
 			foreach ($sort as $column => $order) {
 				$this->sql = $this->queryHelper->orderBy((string) $column, $order);