MySQL中的UNION查詢

Question

我有這兩個查詢。

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

一切正常。

但是當我嘗試將這兩個查詢合並為union ，

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

它以升序提供第二個查詢的輸出，但在查詢中以降序提供。

Answer 1

您可以嘗試如下。

(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

這樣嘗試

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

您可以嘗試以下方法：

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

我通過以下方法解決了該查詢。

選擇* from blog_post，其中isDelete = 0排序（大小寫為pOrder，則為0，然后（從Blog_post選擇Max（pOrder）+ 1），否則pOrder結束）asc，postID desc

感謝您對這個問題的評論，我只是在處理它，上面的查詢使我很滿意。