delete from 表名 where id not in (select d.id from (SELECT id FROM 表名 GROUP BY c1,c2,c3,c4)as d) #去重复,把url重复,且区为空的中去掉.select * from TABLE where url in (select u.url from (select * from TABLE where id not in (select d.id from (SELECT id FROM TABLE GROUP
删除重复数据保留name中id最小的记录 delete from order_info where id not in (select id from (select min(id) as id from order_info group by order_number) as b); delete from table where id not in (select min(id) from table group by name having count(name)>1) and id i
由于开发新的系统,需要将之前一个老的C/S应用的数据按照新的数据设计导入到新库中.此过程可能涉及到表结构不一致.大数据量(千万级,甚至上亿)等情况,包括异构数据的抽取.清洗等等工作.部分复杂的工作需要我们的DBA写代码用程序在JDBC或者Delphi中解决,而大部分稍简单的数据的迁移需要一个强大的ETL工具来解决.某日,技术经理让我找一个满足我们项目数据迁移需求的稳定.高效ETL工具.google了几把,网上大致有下列几款软件资料较多:Oracle的OWB(Oracle Warehouse Bu
由于开发新的系统,需要将之前一个老的C/S应用的数据按照新的数据设计导入到新库中.此过程可能涉及到表结构不一致.大数据量(千万级,甚至上亿)等情况,包括异构数据的抽取.清洗等等工作.部分复杂的工作需要我们的DBA写代码用程序在JDBC或者Delphi中解决,而大部分稍简单的数据的迁移需要一个强大的ETL工具来解决.某日,技术经理让我找一个满足我们项目数据迁移需求的稳定.高效ETL工具.google了几把,网上大致有下列几款软件资料较多:Oracle的OWB(Oracle Warehouse Bu
删除表中重复记录,只保留一条: delete from 表名 where 字段ID in (select * from (select max(字段ID) from 表名 group by 重复的字段 having count(重复的字段) > 1) as b); 查询重复数据select * from prpmlossitem where CaseNo in ( select CaseNo from prpmlossitem group by CaseNo having count(CaseN
1.查询表中重复数据.select * from peoplewhere peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)2.删除表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断,只留有rowid最小的记录delete from people where peopleId in (select peopleId
数据重复分为两种情况:一种是每个字段都相同的完全重复,第二种是部分字段重复的结果集.比如Name字段重复,而其他字段不一定重复或者重复可以忽略. 第一种情况比较容易解决,使用select distinct * from tableName就可以得到无重复记录的结果集. 如果该表需要删除重复的记录(重复记录保留一条),可以按一下方法删除: select distinct * into #Tmp from tableName drop table tableName select * into ta
例子:表名 Paper .通过字段PaperID查找重复数据. 1 --查询某表中重复的数据 select * from Paper group by PaperID having count(*)>1; 2--删除重复行数,只剩不重复的记录(rowid为sqlite自带字段) delete from Paper where Paper.rowid not in (select MAX(Paper.rowid) from Paper group by PaperID);