怎样优化这条oracle sql语句
语句如下:
select /*+user_hash(a b c)*/
b.id,
b.name,
count(c.number)
from v_useinfo a, v_info c, t_region b
where NOT EXISTS (select number
from v_pdreport
where number = a.number
and ddate >= sysdate-1
and ddate < sysdate)
and a.status in (3,4)
and a.number = c.number
and a.stype = 1
and c.id = b.id
group by b.id, b.name;
说明 表v_useinfo ,v_info ,v_pdreport数据量非常大,该怎样优化这条语句?