MySQL如何快速删除重复记录

如何删除重复数据, 只保留一条

drop table if exists temp_dm_patientinfo_id;
create table temp_dm_patientinfo_id
as
select
record_id,                   -- 重复键
max(id) max_id
from dm_patientinfo    -- 重复记录所在表
group by record_id
having count(1)>1 ;

delete a from dm_patientinfo a, temp_dm_patientinfo_id b
where a.record_id = b.record_id and a.id < b.max_id;

drop table if exists temp_dm_patientinfo_id;