处理重复数据

查找表中多余的重复记录

select *
  from data_tax_digital_stamps t
 where (t.certificatenm) in (select t.certificatenm
                               from data_tax_digital_stamps t
                              group by t.certificatenm
                             having count(*) > 1);

删除表中多余的重复记录，只留有rowid最小的记录
delete from data_tax_digital_stamps t
 where (t.certificatenm) in (select t.certificatenm
                               from data_tax_digital_stamps t
                              group by t.certificatenm
                             having count(*) > 1)
   and rowid not in (select min(rowid)
                       from data_tax_digital_stamps t
                      group by t.certificatenm
                     having count(*) > 1)