diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index dbee2aaad04..f5b22c2d004 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -642,6 +642,7 @@ struct Query_cache_query_flags
   ulong sql_mode;
   ulong max_sort_length;
   ulong group_concat_max_len;
+  ulong default_week_format;
   MY_LOCALE *lc_time_names;
 };
 #define QUERY_CACHE_FLAGS_SIZE sizeof(Query_cache_query_flags)