delete from tb1   where id in(

select t2.minnum from(select MIN(t1.id) as minnum,t1.col1 as ars ,COUNT(1) as cx  from tb1 t1 group by t1.col1

)t2)

select * from tb1 where id in(

select t2.minnum from

(select  min(t.id) as minnum,t.col1,COUNT(1) cx from tb1 t  group by t.col1  having COUNT(t.col1)>1) t2)

只查询有重复的部分

select * from tb1;

11 1

14 2

17 3

18 333

19 4