SQL語句實現(xiàn)刪除重復(fù)記錄并只保留一條

更新時間：2015年06月16日 10:25:51 投稿：junjie

這篇文章主要介紹了SQL語句實現(xiàn)刪除重復(fù)記錄并只保留一條,本文直接給出實現(xiàn)代碼,并給出多種查詢重復(fù)記錄的方法,需要的朋友可以參考下

復(fù)制代碼代碼如下:

delete WeiBoTopics where Id in(select max(Id) from WeiBoTopics group by WeiBoId,Title having COUNT(*) > 1); 

SQL：刪除重復(fù)數(shù)據(jù)，只保留一條用SQL語句,刪除掉重復(fù)項只保留一條在幾千條記錄里,存在著些相同的記錄,如何能用SQL語句,刪除掉重復(fù)的呢

1、查找表中多余的重復(fù)記錄，重復(fù)記錄是根據(jù)單個字段（peopleId）來判斷

復(fù)制代碼代碼如下:

 select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)

2、刪除表中多余的重復(fù)記錄，重復(fù)記錄是根據(jù)單個字段（peopleId）來判斷，只留有rowid最小的記錄

復(fù)制代碼代碼如下:

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、查找表中多余的重復(fù)記錄（多個字段）

復(fù)制代碼代碼如下:

select * from vitae a where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)

4、刪除表中多余的重復(fù)記錄（多個字段），只留有rowid最小的記錄

復(fù)制代碼代碼如下:

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、查找表中多余的重復(fù)記錄（多個字段），不包含rowid最小的記錄

復(fù)制代碼代碼如下:

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.消除一個字段的左邊的第一位：

復(fù)制代碼代碼如下:

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

7.消除一個字段的右邊的第一位：

復(fù)制代碼代碼如下:

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

8.假刪除表中多余的重復(fù)記錄（多個字段），不包含rowid最小的記錄

復(fù)制代碼代碼如下:

update vitae set ispass=-1 where peopleId in (select peopleId from vitae group by peopleId,seq having count(*) > 1) and seq in （select 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)

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