mysql分组求和求最大值

T是表，G是组，V是值：

分组、求和、求最大值：select G,MAX(SUM(V)) V1 from T group by G

求比值：

select T.G,SUM(T.V)/A.V1

from T,

(select G,MAX(SUM(V)) V1 from T group by G) A

where T.G=A.G

group by T.G

试试看，我没测试。

select (select avg(sales) from 表名 b where (a.date-b.date) between 0 and 20) as [前20日平均销量],* from 表名 a

SELECT i.uid,sum(deposit+ddeposit+money) as allmoney FROM

另外,因为你是多个表的左联接,考虑到有NULL记录的存在,建议你用函数ifnull处理下,避免由于NULL而造成结果有误,最终改成这样:

SELECT i.uid,sum(ifnull(deposit,0)+ifnull(ddeposit,0)+ifnull(money,0)) as allmoney

FROM pw_memberinfo i LEFT JOIN pw_members m ON m.uid=i.uid LEFT JOIN pw_memberdata d ON i.uid=d.uid

where ifnull(deposit,0)+ifnull(ddeposit,0)+ifnull(money,0)>2000

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