diff --git a/t-sql/README.md b/t-sql/README.md
index 5d45285..28c30ac 100644
--- a/t-sql/README.md
+++ b/t-sql/README.md
@@ -13,6 +13,12 @@ commit; -- if all ok
 rollback; --if not ok
 ```
 
+## limit
+
+```
+... LIMIT 5 at the end, would become SELECT TOP (5) at the start.
+```
+
 ## check memory of DB server
 
 ```