diff --git a/phpBB/includes/cache/driver/memory.php b/phpBB/includes/cache/driver/memory.php
index bc08494c0c..e4da5767cf 100644
--- a/phpBB/includes/cache/driver/memory.php
+++ b/phpBB/includes/cache/driver/memory.php
@@ -294,7 +294,7 @@ abstract class phpbb_cache_driver_memory extends phpbb_cache_driver_base
 		if (!preg_match('/FROM \\(?(`?\\w+`?(?: \\w+)?(?:, ?`?\\w+`?(?: \\w+)?)*)\\)?/', $query, $regs))
 		{
 			// Bail out if the match fails.
-			return;
+			return $query_result;
 		}
 		$tables = array_map('trim', explode(',', $regs[1]));