有一个表MX有100多万条记录,我基本这个表建了一个视图v_MX:
create or replace view v_MX as
select a.费用id,
sum(decode(a.组成序号,1,a.组成金额)) as f1,
sum(decode(a.组成序号,2,a.组成金额)) as f2,
sum(decode(a.组成序号,3,a.组成金额)) as f3,
sum(decode(a.组成序号,4,a.组成金额)) as f4,
sum(decode(a.组成序号,5,a.组成金额)) as f5
from MX a
group by a.费用id;
执行select * from v_MX;时,速度很慢,要是跟别的表再关联的话,就更不用说了.
我对费用id和组成序号都分别建了索引,但是我对
select * from v_MX;做explain plan 时都是全表扫描,索引一点用也没有
请哪位高手帮忙看看,这个要怎么优化?!
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