我的sql语句如下,执行没问题,就是速度太慢,这个表有100多万条
select b.product,b.vendor,a.price
from
(select product,vendor,max(time) as lastdate from table1
where time < = '20021218'
group by product, vendor
) b,
table1 a
where b.product = a.product
and b.vendor = a.vendor
and b.lastdate = a.time