使用SQL語(yǔ)句怎么刪除重復(fù)記錄并只保留一條

本篇文章為大家展示了使用SQL語(yǔ)句怎么刪除重復(fù)記錄并只保留一條，內(nèi)容簡(jiǎn)明扼要并且容易理解，絕對(duì)能使你眼前一亮，通過(guò)這篇文章的詳細(xì)介紹希望你能有所收獲。

1、查找表中多余的重復(fù)記錄，重復(fù)記錄是根據(jù)單個(gè)字段（peopleId）來(lái)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(gè)字段（peopleId）來(lái)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(gè)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(gè)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(gè)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(gè)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(gè)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(gè)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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