为什么查询速度这么慢
我建了张临时表temp
insert into temp (uni_no,item_name,price) select uni_no,item_name,price from product where uni_no like '%%' and item_name like '%深刻%' and author like '%%'
这句执行很快
select b.uni_no uni_no,b.item_name item_name,b.price price,nvl(sum(decode(rtrim(a.salecard_kind),'1',sale_num,0)),0) fscs,
nvl(sum(decode(rtrim(a.card_kind),'8',num,0)),0) tscs,
nvl(sum(decode(rtrim(a.card_kind),'1',hcost,0)),0) fsmy,
nvl(sum(decode(rtrim(a.card_kind),'8',hcost,0)),0) tsmy,
nvl(sum(decode(rtrim(a.card_kind),'1',hamt,0)),0) fssy,
nvl(sum(decode(rtrim(a.card_kind),'8',hamt,0)),0) tssy,
nvl(sum(decode(rtrim(a.status),'10',num,0)),0) hkcs,
nvl(sum(decode(rtrim(a.status),'10',hamt,0)),0) hksy,
nvl(sum(decode(rtrim(a.status),'10',cost,0)),0) hkmy from subcard a,temp b
where a.uni_no=b.uni_no and a.date>='2000-5-19' and a.date<='2009-5-19'
group by b.uni_no,b.item_name,b.price
这句很慢,为什么啊?怎么才能优化。