MySQL查詢表內重複記錄

標籤：

(一)

1、尋找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 peoplewhere 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，只留有一個記錄delete from peoplewhere peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)and min(id) not in (select id from people group by peopleId having count(peopleId )>1) 3、尋找表中多餘的重複記錄（多個欄位）select * from vitae awhere (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 awhere (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、尋找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 awhere (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；?

1	Select Name,Count(*) From A Group By Name Having Count(*) > 1

 

 如果還查性別也相同大則如下:?

1	Select Name,sex,Count(*) From A Group By Name,sex Having Count(*) > 1

（三）

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

set rowcount 0

 

MySQL查詢表內重複記錄