给大神们看条sql。看看如何优化，在不改变表结构得情况。

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SELECT c.unit,

sum(case when (i.deep=1 OR i.deep>1) and i.type=0 then s.deep1 else 0 end) AS deep1,
sum(case when (i.deep=1 OR i.deep>1) and i.type=1 then s.deep1 else 0 end) AS deep5,
sum(case when (i.deep=1 OR i.deep>1) and i.type=2 then s.deep1 else 0 end) AS deep9,
sum(case when (i.deep=1 OR i.deep>1) and i.type=3 then s.deep1 else 0 end) AS deep13,
sum(case when (i.deep=2 OR i.deep>2) and i.type=0 then s.deep2 else 0 end) AS deep2,
sum(case when (i.deep=2 OR i.deep>2) and i.type=1 then s.deep2 else 0 end) AS deep6,
sum(case when (i.deep=2 OR i.deep>2) and i.type=2 then s.deep2 else 0 end) AS deep10,
sum(case when (i.deep=2 OR i.deep>2) and i.type=3 then s.deep2 else 0 end) AS deep14,
sum(case when (i.deep=3 OR i.deep>3) and i.type=0 then s.deep3 else 0 end) AS deep3,
sum(case when (i.deep=3 OR i.deep>3) and i.type=1 then s.deep3 else 0 end) AS deep7,
sum(case when (i.deep=3 OR i.deep>3) and i.type=2 then s.deep3 else 0 end) AS deep11,
sum(case when (i.deep=3 OR i.deep>3) and i.type=3 then s.deep3 else 0 end) AS deep15,
sum(case when i.deep=4 and i.type=0 then s.deep4 else 0 end) AS deep4,
sum(case when i.deep=4 and i.type=1 then s.deep4 else 0 end) AS deep8,
sum(case when i.deep=4 and i.type=2 then s.deep4 else 0 end) AS deep12,
sum(case when i.deep=4 and i.type=3 then s.deep4 else 0 end) AS deep16,
sum(i.deep) AS zf

FROM info AS i LEFT JOIN credits AS s ON i.type=s.type LEFT JOIN contact AS c ON i.uid=c.uid $wansql GROUP BY i.uid ORDER BY zf DESC

Deep

type

SUM

1 条回复 • 1970-01-01 08:00:00 +08:00

dilfish

2013-03-13 17:24:01 +08:00

每个表中的数据量是多少呢
数据库软件是什么呢