SQL Sever 刪除重複數據只剩一條

use book

   go

  

   create table ##T1(

     n int,

     a nvarchar(20)  

   )

  

   --查詢重複記錄，插入臨時表

   insert into ##T1(n,a) 

   select suid,WorkID from HR_Duty_EmpSchedule_M

   where WorkID in (select WorkID  from HR_Duty_EmpSchedule_M  group by WorkID having count(WorkID) > 1)

   and DutyDate ='2018/11/26'

   order by WorkID

  

  select * from ##T1

  

   create table ##T2(

      m int,

      a nvarchar(20)

   )

   --查詢

  

   select min(n) as N  from ##T1 group by a having count(a)>1

  

   insert into ##T2(m,a)

   select n,a from ##T1 where n not in ( select min(n) as N  from ##T1 group by a having count(a)>1)

  

   select * from ##T2

  

   select * from HR_Duty_EmpSchedule_M X,##T2 Y  where X.SUID=Y.m order by WorkID

  

   --delete from HR_Duty_EmpSchedule_M  where SUID in (select m from ##T2)

  

   

   drop table ##T1

   drop table ##T2