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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