sqlserver常用操作——判断关键字段是否重复插入记录

发布时间：2020-12-12 15:04:26 所属栏目：MsSql教程来源：网络整理

导读：sqlserver常用操作（2）——判断关键字段是否重复插入记录插入数据，判断这条数据是否重复，游标中采用的思想是逐条循环判断是否添加。方法一： insert into dbo.News (NewsTitle,Typeid,TypeName,[content]) select NewsTitle,[content] from dbo.News2 b

sqlserver常用操作（2）——判断关键字段是否重复插入记录

插入数据，判断这条数据是否重复，游标中采用的思想是逐条循环判断是否添加。
方法一：
insert into
dbo.News (NewsTitle,Typeid,TypeName,[content])
select NewsTitle,[content]
from dbo.News2 b
where b.NewsTitle not in(select??NewsTitle from dbo.News)

方法二：
insert into
dbo.News (NewsTitle,[content]
from dbo.News2 b
where not exists
(select * from dbo.news where NewsTitle=b.NewsTitle)

游标操作示例一：
declare?? @cur_pos?? int??
declare?? mycursor?? cursor?? for?? select?? NewsTitle,Typeid?? from?? dbo.News??
declare?? @col1?? char(10)??
declare?? @col2?? char(10)????
open?? mycursor??
fetch next from mycursor?? into?? @col1,@col2??
while?? @@fetch_status<>-1??
begin??
print @col1+@col2
--select?? @cur_pos=@cur_pos+1??
fetch next from??mycursor?? into?? @col1,@col2??
end??
close mycursor
deallocate mycursor

游标操作示例二：
declare @cur_pos int
declare @newsid int
declare @newstitle varchar(20)
declare mycursor cursor for select Newsid,NewsTitle from dbo.News2

open mycursor
fetch next from mycursor into @newsid,@newstitle
while @@fetch_status<>-1
begin
if not exists
(select * from dbo.News where NewsTitle=@newstitle)
????begin
????insert into dbo.News(NewsTitle,[content])
????select NewsTitle,[content]
????from dbo.News2 where NewsId=@newsid
????end
fetch next from mycursor into @newsid,@newstitle
end

close mycursor
deallocate mycursor 转自： http://www.thaught.cn/go.php/category/16/1/2/

（编辑：李大同）

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