最近用的几个sql语句

都在sqlserver数据库下操作，注意sqlserver与mysql和oracle的语法区别

用惯了mysql 和oracle，突然改用sqlserver，有诸多的不习惯，诸多的坑爹，好多的坑，一一跳过一遍才知道，头破血流呀！​

1，建表

create table stuUnion

(

sid int identity primary key,

cid int,

id varchar(500)

)

2 插入数据​

insert into stuUnion

select 1,'a' union

select 1,'b' union

select 2,'c' union

select 2,'d' union

select 3,'e' union

select 3,'f' union

select 3,'g'

3 标量函数（合并不同记录的相同字段）​

create function b(@cid int)

returns varchar(500)

as

begin

declare @s varchar(500)

select @s=isnull(@s+'','')+rtrim(id)+',' from stuUnion where cid=@cid

return @s

end;

4 显示结果​

select cid,dbo.b(cid) as id from stuUnion group by cid

5改造标量函数

注意点1 参数类型，int 和 String​

2 ​  where VID like '%'+@VID+'%'

create function c(@VID nvarchar)

returns varchar(500)

as

begin

declare @s varchar(500)

select @s=isnull(@s+'','')+rtrim(items)+' ' from cus_checks where VID like '%'+@VID+'%'

return @s

end;

select VID,dbo.c(VID) as 检查项目 from cus_checks group by VID

6修改字段​

sp_rename 'cus_checks.check','items','column'

7不用标量函数进行查询取值 ​

select VID,items=STUFF((select DISTINCT ' '+rtrim(items)+' ' from cus_checks where st.VID=VID for XML path('')),1,1,'')  from cus_checks st group by VID

8 对表数据进行去重处理​

slect * insert into abc from select DISTINCT VID,Items from cus_checks

9复制去重后的表​

select * into aaa from cus_checks where 1=2

insert into aaa select DISTINCT * from cus_checks