mysql - UNION 在 ORDER BY 和 LIMIT 之后

Question

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:

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 - Incorrect usage of UNION and ORDER BY

重要的是 ORDER BY 仅用于第一个查询。我该如何执行此任务？

Answer 1

您可以使用括号来允许对单个查询使用 ORDER/LIMIT:

(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 */