去重的按某个字段进行去重sql

delete from op_car_owners2 where carnum in(
 select carnum  from(
  select max(carnum ) as carnum ,count(carnum) as count from op_car_owners2 group by carnum having count>1 order by count desc
 ) as tab
)

DELETE from op_car_owners2 where carnum=‘苏A9CC18‘ and phone=‘0‘

原文：http://www.cnblogs.com/shuixinwen/p/4065531.html