Create Table dbo.Employee (
[Id] int
Primary KEY ,
[N
ame] v
Archar(50),
[Age] int,
[Sex] b
IT default 1
)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(1,'James',25,default)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(2,'James',25,default)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(3,'James',25,default)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(4,'Lisa',24,0)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(5,'Lisa',24,0)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(6,'Lisa',24,0)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(7,'Mirsa',23,0)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(8,'Mirsa',23,0)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(9,'Mirsa',23,0)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(10,'John',26,default)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(11,'A
braham',28,default)
Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) Values(12,'Lincoln',30,default)
Delete T From( Select Row_Number() Over(Partition By [Name] Order By (SELECT 0)) As RowNumber,* From Employee) TWhere T.RowNumber > 1;
注意上面的方法只是在重复记录比较少的情况下, 如果重复记录多. DELETE将会非常慢, 最好的方法是复制目标数据到另一个新表,删除
的表,重命名新表为原来的表. 或用临时表, 这样还可以减少数据库事务日志. 看下面的T-SQL:
WITH Dups As
(
Select [ID],[Name],[Age],[Sex]
, ROW_NUMBER() OVER(Partition By [ID] Order By (SELECT 0)) AS rn
FROM Employee
)
Select [ID],[Name],[Age],[Sex]
INTO dbo.EmployeeDups
tmp FROM Dups
WHERE rn=1
DROP TABLE dbo.Employee;
EXEC sp_
rename 'dbo.EmployeeDupsTmp','Employee'