SQL删除重复数据只保留一条 (转载)

--查询重复的记录并显示
select * from [DVP_OF].[dbo].[OF_Ofddntval_dvp]
where (Fundcd+Clsdt+CAST(Naps as nvarchar(100))+CAST(Accnav1 as nvarchar(100))) in
  (SELECT  (Fundcd+Clsdt+CAST(Naps as nvarchar(100))+CAST(Accnav1 as nvarchar(100)))
  FROM OF_Ofddntval_dvp
  GROUP BY Fundcd,Clsdt,Naps,Accnav1
  HAVING COUNT (*) >1)
 and Id not in
  (SELECT  MIN(Id)
  FROM OF_Ofddntval_dvp
  GROUP BY Fundcd,Clsdt,Naps,Accnav1
  HAVING COUNT (*) >1)
  
--删除重复的记录
delete from [DVP_OF].[dbo].[OF_Ofddntval_dvp]
where (Fundcd+Clsdt+CAST(Naps as nvarchar(100))+CAST(Accnav1 as nvarchar(100))) in
  (SELECT  (Fundcd+Clsdt+CAST(Naps as nvarchar(100))+CAST(Accnav1 as nvarchar(100)))
  FROM OF_Ofddntval_dvp
  GROUP BY Fundcd,Clsdt,Naps,Accnav1
  HAVING COUNT (*) >1)
 and Id not in
  (SELECT  MIN(Id)
  FROM OF_Ofddntval_dvp
  GROUP BY Fundcd,Clsdt,Naps,Accnav1
  HAVING COUNT (*) >1)
用SQL语句,删除掉重复项只保留一条
在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢
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   peopleName in (select peopleName    from people group by peopleName      having count(peopleName) > 1) 
and   peopleId not in (select min(peopleId) from people group by peopleName     having count(peopleName)>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)   

6.消除一个字段的左边的第一位：

update tableName set [Title]=Right([Title],(len([Title])-1)) where Title like '村%'

7.消除一个字段的右边的第一位：

update tableName set [Title]=left([Title],(len([Title])-1)) where Title like '%村'

8.假删除表中多余的重复记录（多个字段），不包含rowid最小的记录 
update vitae set ispass=-1
where peopleId in (select peopleId from vitae group by peopleId