如何用sql语句查询和删除表中重复数据
2012-04-17 09:27
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如何用sql语句查询和删除表中重复数据
1、查询表中重复数据(单字段)
Select * From 表 Where 字段1 In (Select 字段1 From 表 Group By 字段1 Having Count(字段1) > 1)
2、删除表中多余的重复记录,只留有rowid最小的记录(单字段)
Delete From 表
Where 字段1 In (Select 字段1 From 表 Group By 字段1 Having Count(字段1) > 1) And
Rowid Not In (Select Min(Rowid) From 表 Group By 字段1 Having Count(字段1) > 1)
3、查找表中多余的重复记录(多个字段)
Select * From 表 a Where (a.字段1, a.字段2) In (Select 字段1, 字段2 From 表 Group By 字段1, 字段2 Having Count(*) > 1)
4、删除表中多余的重复记录,只留有rowid最小的记录(多个字段)
Delete From 表 a
Where (a.字段1, a.字段2) In (Select 字段1, 字段2 From 表 Group By 字段1, 字段2 Having Count(*) > 1) And
Rowid Not In (Select Min(Rowid) From 表 Group By 字段1, 字段2 Having Count(*) > 1)
5.删除多于的重复记录(单个字段,多个字段)
delete from table where id not in ( select min(id) from table group by name)
或者
delete from table where id not in ( select min(id) from table group by 字段1,字段2)
6.删除多余的重复记录(单个字段,多个字段)
delete from table where id in ( select max(id) from table group by name 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.字段1, a.字段2) In (Select 字段1, 字段2 From 表 Group By 字段1, 字段2 Having Count(*) > 1) And
Rowid Not In (Select Min(Rowid) From 表 Group By 字段1, 字段2 Having Count(*) > 1)
查单个字段的重复次数
Select Name,sex,Count(*) From A Group By Name,sex Having Count(*) > 1
1、查询表中重复数据(单字段)
Select * From 表 Where 字段1 In (Select 字段1 From 表 Group By 字段1 Having Count(字段1) > 1)
2、删除表中多余的重复记录,只留有rowid最小的记录(单字段)
Delete From 表
Where 字段1 In (Select 字段1 From 表 Group By 字段1 Having Count(字段1) > 1) And
Rowid Not In (Select Min(Rowid) From 表 Group By 字段1 Having Count(字段1) > 1)
3、查找表中多余的重复记录(多个字段)
Select * From 表 a Where (a.字段1, a.字段2) In (Select 字段1, 字段2 From 表 Group By 字段1, 字段2 Having Count(*) > 1)
4、删除表中多余的重复记录,只留有rowid最小的记录(多个字段)
Delete From 表 a
Where (a.字段1, a.字段2) In (Select 字段1, 字段2 From 表 Group By 字段1, 字段2 Having Count(*) > 1) And
Rowid Not In (Select Min(Rowid) From 表 Group By 字段1, 字段2 Having Count(*) > 1)
5.删除多于的重复记录(单个字段,多个字段)
delete from table where id not in ( select min(id) from table group by name)
或者
delete from table where id not in ( select min(id) from table group by 字段1,字段2)
6.删除多余的重复记录(单个字段,多个字段)
delete from table where id in ( select max(id) from table group by name 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.字段1, a.字段2) In (Select 字段1, 字段2 From 表 Group By 字段1, 字段2 Having Count(*) > 1) And
Rowid Not In (Select Min(Rowid) From 表 Group By 字段1, 字段2 Having Count(*) > 1)
查单个字段的重复次数
Select Name,sex,Count(*) From A Group By Name,sex Having Count(*) > 1
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