【數據庫】sql語句刪除重複數據

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

1、查找表中多餘的重複記錄，重複記錄是根據單個字段（trans_id）來判斷

select *
  from intf_task_instance t
 where t.trans_id in (select trans_id
                        from intf_task_instance
                       group by (trans_id, intf_task_instance_id)
                      having count(trans_id) > 1);

2、刪除表中多餘的重複記錄，重複記錄是根據單個字段（intf_task_instance_id）來判斷，只留有rowid最小的記錄

delete from intf_task_instance t
 where t.intf_task_instance_id in
       (select intf_task_instance_id
          from intf_task_instance
         group by intf_task_instance_id
        having count(intf_task_instance_id) > 1)
   and rowid not in (select min(Rowid)
                       from intf_task_instance
                      group by intf_task_instance_id
                     having count(intf_task_instance_id) > 1);

3、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)

4、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)

5、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)