diff --git a/docs/en/14-reference/03-taos-sql/06-select.md b/docs/en/14-reference/03-taos-sql/06-select.md
index c33fef95fb..3b89c4fe5a 100644
--- a/docs/en/14-reference/03-taos-sql/06-select.md
+++ b/docs/en/14-reference/03-taos-sql/06-select.md
@@ -491,15 +491,15 @@ SELECT ... FROM (SELECT ... FROM ...) ...;
 
 :::
 
-## UNION ALL Clause
+## UNION Clause
 
 ```text title=Syntax
 SELECT ...
-UNION ALL SELECT ...
-[UNION ALL SELECT ...]
+UNION [ALL] SELECT ...
+[UNION [ALL] SELECT ...]
 ```
 
-TDengine supports the UNION ALL operator. This means that if multiple SELECT clauses return result sets with the exact same structure (column names, column types, number of columns, order), these result sets can be combined together using UNION ALL. Currently, only the UNION ALL mode is supported, which means that duplicates are not removed during the merging process. In the same SQL statement, a maximum of 100 UNION ALLs are supported.
+TDengine supports the UNION [ALL] operator. This means that if multiple SELECT clauses return result sets with the exact same structure (column names, column types, number of columns, order), these result sets can be combined together using UNION [ALL].
 
 ## SQL Examples
 
diff --git a/docs/zh/14-reference/03-taos-sql/06-select.md b/docs/zh/14-reference/03-taos-sql/06-select.md
index 43418b3b1d..cd6835b55e 100644
--- a/docs/zh/14-reference/03-taos-sql/06-select.md
+++ b/docs/zh/14-reference/03-taos-sql/06-select.md
@@ -491,15 +491,15 @@ SELECT ... FROM (SELECT ... FROM ...) ...;
 
 :::
 
-## UNION ALL 子句
+## UNION 子句
 
 ```txt title=语法
 SELECT ...
-UNION ALL SELECT ...
-[UNION ALL SELECT ...]
+UNION [ALL] SELECT ...
+[UNION [ALL] SELECT ...]
 ```
 
-TDengine 支持 UNION ALL 操作符。也就是说，如果多个 SELECT 子句返回结果集的结构完全相同（列名、列类型、列数、顺序），那么可以通过 UNION ALL 把这些结果集合并到一起。目前只支持 UNION ALL 模式，也即在结果集的合并过程中是不去重的。在同一个 sql 语句中，UNION ALL 最多支持 100 个。
+TDengine 支持 UNION [ALL] 操作符。也就是说，如果多个 SELECT 子句返回结果集的结构完全相同（列名、列类型、列数、顺序），那么可以通过 UNION [ALL] 把这些结果集合并到一起。
 
 ## SQL 示例