From 1044a4a86d0a628ca65e5d40c0e2932c26cbea02 Mon Sep 17 00:00:00 2001 From: dapan1121 Date: Tue, 7 Jan 2025 15:00:57 +0800 Subject: [PATCH] fix: union clause description error --- docs/en/14-reference/03-taos-sql/06-select.md | 8 ++++---- docs/zh/14-reference/03-taos-sql/06-select.md | 8 ++++---- 2 files changed, 8 insertions(+), 8 deletions(-) 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 c33fef95fb13..3b89c4fe5ae5 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 43418b3b1db6..cd6835b55eff 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