return @str
end
go
–调用：
select [name],dbo.join_str([name]) role2 from a_test group by [name]
–select distinct name,dbo.uf_test(name) from a_test
* 快速比较结构相同的两表
结构相同的两表，一表有记录3万条左右，一表有记录2万条左右，我怎样快速查找两表的不同记录？
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给你一个测试方法，从northwind中的orders表取数据。
select * into n1 from orders
select * into n2 from orders
select * from n1
select * from n2
–添加主键，然后修改n1中若干字段的若干条
alter table n1 add constraint pk_n1_id primary key (OrderID)
alter table n2 add constraint pk_n2_id primary key (OrderID)
select OrderID from (select * from n1 union select * from n2) a group by OrderID having count(*) > 1
应该可以，而且将不同的记录的ID显示出来。
下面的适用于双方记录一样的情况，
select * from n1 where orderid in (select OrderID from (select * from n1 union select * from n2) a group by OrderID having count(*) > 1)
至于双方互不存在的记录是比较好处理的
–删除n1,n2中若干条记录
delete from n1 where orderID in (‘10728′,’10730’)
delete from n2 where orderID in (‘11000′,’11001’)
–*************************************************************
— 双方都有该记录却不完全相同
select * from n1 where orderid in(select OrderID from (select * from n1 union select * from n2) a group by OrderID having count(*) > 1)
