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sql 查詢結(jié)果合并union all用法_數(shù)據(jù)庫技巧

 更新時(shí)間：2009年11月08日 23:32:28   作者：  
sql語句查詢結(jié)果合并union all用法_數(shù)據(jù)庫技巧，需要的朋友可以參考下。
復(fù)制代碼 代碼如下:

--合并重復(fù)行
select * from A
union
select * from B


--不合并重復(fù)行
select * from A
union all
select * from B


按某個(gè)字段排序
--合并重復(fù)行
select *
from (
select * from A
union
select * from B) AS T
order by 字段名

--不合并重復(fù)行
select *
from (
select * from A
union all
select * from B) AS T
order by 字段名

//sql server版
Select * From (
select top 2 id,adddate,title,url from bArticle where ClassId=1 order by adddate desc) A
Union All
Select * From (
select top 2 id,adddate,title,url from bArticle where ClassId=2 order by adddate desc) B
Union All
Select * From (
select top 2 id,adddate,title,url from bArticle where ClassId=3 order by adddate desc) C
Union All
Select * From (
select top 2 id,adddate,title,url from bArticle where ClassId=4 order by adddate desc) D


//mysql版
Select * From (
select id,adddate,title,url from bArticle where ClassId=1 order by adddate desc limit 0,2) A
Union All
Select * From (
select id,adddate,title,url from bArticle where ClassId=2 order by adddate desc limit 0,2) B
Union All
Select * From (
select id,adddate,title,url from bArticle where ClassId=3 order by adddate desc limit 0,2) C
Union All
Select * From (
select id,adddate,title,url from bArticle where ClassId=4 order by adddate desc limit 0,2) D

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