sql 查询结果合并union all用法_数据库技巧
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2023-12-13 12:12:58
复制代码 代码如下:--合并重复行 select * from a union select * from b --不合并重复行 select * from a union...
复制代码 代码如下:
--合并重复行
select * from a
union
select * from b
--不合并重复行
select * from a
union all
select * from b
按某个字段排序
--合并重复行
select *
from (
select * from a
union
select * from b) as t
order by 字段名
--不合并重复行
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