select * from
(select * from a
where x='xxxx'
union all
select * from b
where y='yyyy'
union all
select * from c
where z='zzzz'and z1='fdsfs'
)
order by id1,id2,id3,id4,id5,id6
如果不加order by 速度可以,一加后,将近1分钟,像这样也无法见索引,怎么解决?
(select * from a
where x='xxxx'
union all
select * from b
where y='yyyy'
union all
select * from c
where z='zzzz'and z1='fdsfs'
)
order by id1,id2,id3,id4,id5,id6
如果不加order by 速度可以,一加后,将近1分钟,像这样也无法见索引,怎么解决?
解决方案 »
免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货