mysql多字段组合删除重复行

delete
from boll_param
where id in (
  select a.id
  from (
         select id
         from boll_param
         where (symbol, time_frame, ma, k, std, n, 回测起始日期, 回测结束日期, 交易方向) in (
           select symbol,
                  time_frame,
                  ma,
                  k,
                  std,
                  n,
                  回测起始日期,
                  回测结束日期,
                  交易方向
           from boll_param
           group by symbol, time_frame, ma, k, std, n, 回测起始日期, 回测结束日期, 交易方向
           having count(*) > 1
         )
           and id not in (
           select minid
           from (
                  select min(id) as minid
                  from boll_param
                  group by symbol, time_frame, ma, k, std, n, 回测起始日期, 回测结束日期, 交易方向
                  having count(*) > 1
                ) dt
         )) a
)