本文介绍了ORDER BY 和 LIMIT 后的 UNION的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我的目标是执行两个不同的查询,然后将它们组合起来.
我的代码是:
My goal is to execute two different queries and then combine them.
My code is:
SELECT * FROM some tables WHERE ... ORDER BY field1 LIMIT 0,1
UNION
SELECT * FROM some tables WHERE ...
我收到以下错误:
#1221 - UNION 和 ORDER BY 的错误使用
#1221 - Incorrect usage of UNION and ORDER BY
ORDER BY 仅用于第一个查询很重要.我该如何执行此任务?
It is important that ORDER BY is only for the first query. How can I perform this task?
推荐答案
您可以使用括号来允许对单个查询使用 ORDER
/LIMIT
:
You can use parenthesis to allow the use of ORDER
/LIMIT
on individual queries:
(SELECT * FROM some tables WHERE ... ORDER BY field1 LIMIT 0, 1)
UNION
(SELECT * FROM some tables WHERE ...)
ORDER BY 1 /* optional -- applies to the UNIONed result */
LIMIT 0, 100 /* optional -- applies to the UNIONed result */
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