DB2 刪除重複記錄

1、查詢表中多餘的重複記錄，重複記錄是根據單個欄位（peopleId）來判斷 select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)

2、刪除表中多餘的重複記錄，重複記錄是根據單個欄位（peopleId）來判斷，只留有rowid最小的記錄
delete from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1) and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1)

3、查詢表中多餘的重複記錄（多個欄位）
select * from vitae a where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)

 4、刪除表中多餘的重複記錄（多個欄位），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)

5、查詢表中多餘的重複記錄（多個欄位），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)

(二)比方說在A表中存在一個欄位“name”，而且不同記錄之間的“name”值有可能會相同，現在就是需要查詢出在該表中的各記錄之 間，“name”值存在重複的項； Select Name,Count(*) From A Group By Name Having Count(*) > 1 如果還查性別也相同大則如下: Select Name,sex,Count(*) From A Group By Name,sex Having Count(*) > 1

 (三)方法一 declare @max integer,@id integer declare cur_rows cursor local for select 主欄位,count(*) from 表名 group by 主欄位 having count(*) >； 1 open cur_rows fetch cur_rows into @id,@max while @@fetch_status=0 begin select @max = @max -1 set rowcount @max delete from 表名 where 主欄位 = @id fetch cur_rows into @id,@max end close cur_rows

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