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博客园 - 伊凡

项目管理检查清单-项目规划 项目管理检查清单-项目启动 一语道破项目管理知识体系五大过程组 项目经理应具备的9种能力 项目经理在项目各阶段的工作重点-更新版 优秀项目经理必备的8个要素 oracle表空间表分区详解及oracle表分区查询使用方法(转+整理) oracle表空间不足相关问题解决办法 Oracle系统表整理+常用SQL语句收集 wm_concat函数的排序问题 Oracle树查询及相关函数 racle SQL性能优化 oracle存储过程常用技巧 详解:数据库名、实例名、ORACLE_SID、数据库域名、全局数据库名、服务名及手工脚本创建oracle数据库 用友ERP-U8最新破解(再次更新版本,附安装过程中的解决办法) 轻松三步教你配置Oracle—windows环境 非常好的Oracle教程【转】 Oracle新表使用序列(sequence)作为插入值,初始值不是第一个,oraclesequence 大数据学习资源汇总
Oracle 删除重复数据只留一条
伊凡 · 2017-02-18 · via 博客园 - 伊凡

查询及删除重复记录的SQL语句

1、查找表中多余的重复记录,重复记录是根据单个字段(Id)来判断

select * from 表 where Id in (select Id from 表 group byId having count(Id) > 1)

2、删除表中多余的重复记录,重复记录是根据单个字段(Id)来判断,只留有rowid最小的记录

DELETE from 表 WHERE (id) IN ( SELECT id FROM 表 GROUP BY id HAVING COUNT(id) > 1) AND ROWID NOT IN (SELECT MIN(ROWID) FROM 表 GROUP BY id HAVING COUNT(*) > 1);

3、查找表中多余的重复记录(多个字段)

select * from 表 a where (a.Id,a.seq) in(select Id,seq from 表 group by Id,seq having count(*) > 1)

4、删除表中多余的重复记录(多个字段),只留有rowid最小的记录

delete from 表 a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count() > 1) and rowid not in (select min(rowid) from 表 group by Id,seq having count()>1)

5、查找表中多余的重复记录(多个字段),不包含rowid最小的记录

select * from 表 a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count() > 1) and rowid not in (select min(rowid) from 表 group by Id,seq having count()>1)