distinct

需求：
发现一个表里的res_id数据有重复
想把res_id 重复的都去掉

先备份表t_resource_tmcp_back

insert into t_resource_tmcp_back select * from t_resource_tmcp;

删除现有的表delete from t_resource_tmcp
然后

insert into t_resource_tmcp  
select k.id,k.res_id,k.tmtype_id ,k.tmcp_id,k.alloc_ratio ,k.valid_date from (
 select t.*, count(distinct t.res_id ) from t_resource_tmcp_back as t group by t.res_id 
) as k