用SQL語句,刪除掉重複項只保留一條

用SQL語句,刪除掉重複項只保留一條

在幾千條記錄裏,存在着些相同的記錄,如何能用SQL語句,刪除掉重複的呢 一、查找表中多餘的重複記錄，重複記錄是根據單個字段（peopleId）來判斷 select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1) 二、刪除表中多餘的重複記錄，重複記錄是根據單個字段（peopleId）來判斷，只留有rowid最小的記錄 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) 三、查找表中多餘的重複記錄（多個字段） select * from vitae a where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1) 四、刪除表中多餘的重複記錄（多個字段），只留有rowid最小的記錄 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) 五、查找表中多餘的重複記錄（多個字段），不包含rowid最小的記錄 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： 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： update tableName set [Title]=left([Title],(len([Title])-1)) where Title like '%村' 8.假刪除表中多餘的重複記錄（多個字段），不包含rowid最小的記錄 update vitae set ispass=-1 where peopleId in (select peopleId from vitae group by peopleId