先在NNO, STime上建立索引Select NNO, STime, n1, n2....
from a inner Join (select NNO, MAX(STime) stime
from a group by NNO) b
On a.NNo = b.NNo and a.STime = b.STime
from a inner Join (select NNO, MAX(STime) stime
from a group by NNO) b
On a.NNo = b.NNo and a.STime = b.STime
from a, (select NNO, MAX(STime) stime from a) b
where a.NNo = b.NNo and a.STime = b.STime--就是这样写的啦--在字段NNo,STime上建立复合索引
--在字段STime上建立倒排序的单独索引.
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select NNO, MAX(STime) stime from a
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语句根本不对呀--
from a ,(select NNO, MAX(STime) stime from a group by nno) b
where a.NNo = b.NNo and a.STime = b.STime
from a ,(select NNO, MAX(STime) stime from a group by nno) b
where a.NNo = b.NNo and a.STime = b.STime
字段STime上建立倒排序索引.