步步为营-89-SQL语句(删除重复数据)

Posted 2020-10-07 逍遥小天狼

exec sp_addlinkedserver \'ITSV\',\'\',\'SQLOLEDB\',\'远程服务器名或ip地址\'
exec sp_addlinkedsrvlogin \'ITSV\',\'false\',null,\'用户名\',\'密码\'
exec sp_dropserver \'ITSV\' , \' droplogins \' --关闭连接

select * from openrowset ( \'SQLOLEDB\' , \'sql服务器名\' ; \'用户名\' ; \'密码\',数据库名.dbo.表名)

ps:删除重复数据

--第一步:先找到重复数据
select ProcInstID from record_errorlog
group by ProcInstID
having count(ProcInstID) > 1
--查看一下
select * from record_errorlog 
where ProcInstID in (select ProcInstID from record_errorlog
group by ProcInstID
having count(ProcInstID) > 1);
--第二部 保留ErrorLogID最大的(也就是最新的数据)
delete  from record_errorlog 
where ProcInstID in (select ProcInstID from record_errorlog group by ProcInstID having count(ProcInstID) > 1)
and ErrorLogID not in (select max(ErrorLogID) from  record_errorlog group by ProcInstID having count(ProcInstID )>1);

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