sqlserver 比较两个表的列的实现代码。
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

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MySQL is suitable for beginners because it is easy to use and powerful. 1.MySQL is a relational database, and uses SQL for CRUD operations. 2. It is simple to install and requires the root user password to be configured. 3. Use INSERT, UPDATE, DELETE, and SELECT to perform data operations. 4. ORDERBY, WHERE and JOIN can be used for complex queries. 5. Debugging requires checking the syntax and use EXPLAIN to analyze the query. 6. Optimization suggestions include using indexes, choosing the right data type and good programming habits.


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