Question

我有两个问题。

select * from blog_post where isDelete=0 
          and pOrder !=0 order by pOrder asc
select * from blog_post where isDelete=0 
          and pOrder=0 order by postID desc

工作正常。

但是当我尝试将这两个查询加入union时，

select * from 
    ((select * from blog_post 
               where isDelete=0 and pOrder !=0 
               order by pOrder asc) 
      union all 
     (select * from blog_post 
               where isDelete=0 and pOrder=0 
               order by postID desc )) as tbl1

它按升序给出第二个查询的输出，但在查询中它按降序排列。

Answer 1

您可以尝试如下。

(select * from blog_post where isDelete=0 and pOrder !=0 order by pOrder asc)
UNION
(select * from blog_post where isDelete=0 and pOrder=0 order by postID desc)

Answer 2

试试这个

select * from(select col1,col2,...colN,'1' as sorting from blog_post where isDelete=0 and pOrder !=0 order by pOrder asc UNION All select col1,col2,...colN,'1' as sorting from blog_post where isDelete=0 and pOrder=0 order by postID desc) temp order by sorting asc,if (sorting=1,pOrder,0) asc,if (sorting=2,postID,0) desc

Answer 3

你可以试试这个：

select * from blog_post where isDelete=0 and pOrder != 0
UNION ALL
select * from blog_post where isDelete=0 and pOrder = 0
order by  pOrder,postID

Answer 4

我通过以下方式解决了这个问题。

从blog_post中选择*，其中isDelete = 0 order by（case pOrder当0时（从blog_post中选择Max（pOrder）+ 1），否则pOrder结束）asc，postID desc

感谢您对此问题的评论，我正在努力解决这个问题并且上面的查询给了我完美的想法。

MySQL中的UNION查询

4 个答案: