mysql union order by 分别排序问题

两种方式:

第一种:

先各自排序,然后通过临时表嵌套再合并结果,注意排序后面必须加入 limit,否则order by不起作用

SELECT * FROM (SELECT * FROM t1 WHERE id IN (1,3,6) ORDER BY utime DESC limit 5) AS a 
UNION ALL
SELECT * FROM (SELECT * FROM t1 WHERE id IN (2,4,5) ORDER BY utime DESC limit 5) AS b
;
第二种:

通过加入临时列px查出所有结果后,再按px,utime排序

SELECT * FROM(
SELECT 0 AS px,id,NAME,utime FROM (SELECT * FROM t1 WHERE id IN (1,3,6)) AS a 
UNION ALL
SELECT  1 AS px,id,NAME,utime FROM (SELECT * FROM t1 WHERE id IN (2,4,5)  ) AS b
) AS c ORDER BY px,utime DESC


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