在oracle中,可以利用count()函数配合select查询语句来查询重复的数据,语法为“select userCode from user group by userCode having count(userCode)1”。 本教程操作环境:Windows10系统、Oracle 11g版、Dell
在oracle中,可以利用count()函数配合select查询语句来查询重复的数据,语法为“select userCode from user group by userCode having count(userCode)>1”。
本教程操作环境:Windows10系统、Oracle 11g版、Dell G3电脑。
oracle怎么查询重复的数据
1、查找表中多余的重复记录,重复记录是根据单个字段(userCode)来判断
select * from user where userCode in (select userCode from user group by userCode having count (userCode) > 1)
2、删除表中多余的重复记录,重复记录是根据单个字段(userCode)来判断,只留有rowid最小的记录
delete from user where userCode in (select userCode from user group by userCode having count (peopleId) > 1) and rowid not in (select min(rowid) from user group by userCode having count(userCode)>1)
3、查找表中多余的重复记录(多个字段)
select * from user a where (a.userCode,a.userName) in (select userCode,userName from user group by userCode,userName 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 user a where (a.userCode,a.userName) in (select userCode,userName from user group by userCode,userName having count(*) > 1) and rowid not in (select min(rowid) from user group by userCode,userName 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 user a where (a.userCode,a.userName) in (select userCode,userName from user group by userCode,userName having count(*) > 1) and rowid not in (select min(rowid) from user group by userCode,userName having count(*)>1)
推荐教程:《Oracle视频教程》
以上就是oracle怎么查询重复的数据的详细内容,更多请关注自由互联其它相关文章!