oracle查重复数据并显示出来

Posted 2023-04-24

SELECT *
FROM t_info a
WHERE ((SELECT COUNT(*)
FROM t_info
WHERE Title = a.Title) > 1)
ORDER BY Title DESC
一。查找重复记录
1。查找全部重复记录
Select * From 表 Where 重复字段 In (Select 重复字段 From 表 Group By 重复字段 Having Count(*)>1)
2。过滤重复记录(只显示一条)
Select * From HZT Where ID In (Select Max(ID) From HZT Group By Title)
注：此处显示ID最大一条记录
二。删除重复记录

1。删除全部重复记录（慎用）
Delete 表 Where 重复字段 In (Select 重复字段 From 表 Group By 重复字段 Having Count(*)>1)
2。保留一条（这个应该是大多数人所需要的 ^_^）
Delete HZT Where ID Not In (Select Max(ID) From HZT Group By Title)
注：此处保留ID最大一条记录
1、查找表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断
select * from people
where 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 from people group by peopleId having count(peopleId) > 1)
and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1)

3、查找表中多余的重复记录（多个字段）
select * from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,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 vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,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 vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)

补充：
有两个以上的重复记录，一是完全重复的记录，也即所有字段均重复的记录，二是部分关键字段重复的记录，比如Name字段重复，而其他字段不一定重复或都重复可以忽略。

1、对于第一种重复，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1条），可以按以下方法删除
select distinct * into #Tmp from tableName
drop table tableName
select * into tableName from #Tmp
drop table #Tmp

发生这种重复的原因是表设计不周产生的，增加唯一索引列即可解决。

2、这类重复问题通常要求保留重复记录中的第一条记录，操作方法如下

假设有重复的字段为Name,Address，要求得到这两个字段唯一的结果集
select identity(int,1,1) as autoID, * into #Tmp from tableName
select min(autoID) as autoID into #Tmp2 from #Tmp group by Name,autoID
select * from #Tmp where autoID in(select autoID from #tmp2) 参考技术A 举例
建表
create table T_BALL
(
b_name VARCHAR2(20),
pan_name VARCHAR2(20)
)
显示重复数据
select t.*
from T_BALL t
where exists (select 1
from t_ball t2
where t2.rowid <> t.rowid
and t.b_name = t2.b_name
and t.pan_name = t2.pan_name) 参考技术B 先通过group by 和having找出有那几行是重复的，再select出重复的数据。

oracle查询重复数据出现次数

话不多数上代码：

　　我在Oracle数据库查数据，发现重复数据，于是我想把重复条数以及具体数据查出来：

　　　　下面是数据

　　

　　然后我需要知道重复多少条 （重复十条，也就是有五条数据相同）

　　SQL：

select COUNT(*) from acsprd.parameters_lowner where pow_low_code in (SELECT  pow_low_code FROM   acsprd.parameters_lowner group by   pow_low_code having COUNT (pow_low_code) > 1)

 

然后拿到重复条数，我需要知道是那些数据重复的：

SQL：

SELECT  pow_low_code FROM   acsprd.parameters_lowner group by   pow_low_code having COUNT (pow_low_code) > 1

 

 

最后查看具体重复数据：

SQL：

SELECT * from  acsprd.parameters_lowner p WHERE p.pow_low_code IN (\'BMW\',\'JAG\',\'LAR\',\'MAUK\',\'VOL\')

 

 

 --------重复记录

 

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