一、问题
给了两个各有四五十个列的表，找出他们相同的列和不同的列
二、查询两个表的列，存在临时表
–#a ,#b都是临时表，当前连接断开后自动删除
–rank() over (order by syscolumns.name desc) as 是sql2005支持的，在每行记录前加上自增序号
–identity(int,1,1) 函数必须要和into联合使用
1、将表的列存入#a–‘desttbl’比较的表名
select * into #a from (select rank() over (order by syscolumns.name desc) as 序号,syscolumns.name
from syscolumns,sysobjects
where syscolumns.[id]=sysobjects.[id]
and sysobjects.[name]=’desttbl’) as t
select * from #a
1 姓名
2 课程
3 id
4 cno
2、将表的列存入#b–‘student’比较的表名
select 序号= identity(int,1,1),syscolumns.name
into #b from syscolumns,sysobjects
where syscolumns.[id]=sysobjects.[id]
and sysobjects.[name]=’student’
select * from #b
1 id
2 name
3 cno
三、分析比较各个表列的异同
用下列语句，或者稍作改动比较
select * from #b where name in (select name from #a)
select * from #a where name not in (select name from #b)
select * from #a a, #b b where a.name=b.name
select * from #a a left join #b b on a.name=b.name