mysql查询SUM的小问题

select

decode(X.col1,0,'null(空)',X.col1)

AS

col1

from

(

SELECT

SUM(CASE

WHEN

col1

=

'yes'

then

1

else

0

end)

AS

col1

FROM

tab1)

X

1、创建三张测试表，

create table pw_memberinfo(uid int, name varchar(20))

create table pw_members(companyid int, uid int)

create table pw_memberdata(uid int, deposit int, ddeposit int, money int)

2、三张表，分别插入测试数据，

insert into pw_members values(1, 1)

insert into pw_members values(1, 2)

insert into pw_members values(1, 3)

insert into pw_memberinfo values(1, 'name_1')

insert into pw_memberinfo values(2, 'name_2')

insert into pw_memberinfo values(3, 'name_3')

insert into pw_memberdata values(1,30,50,150)

insert into pw_memberdata values(2,77,50,12)

insert into pw_memberdata values(3,44,50,82)

3、查看pw_memberdata表中的记录，select * from pw_memberdata t，

4、编写sql语句，

select * from (SELECT i.uid, sum(deposit+ddeposit+money) 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

group by i.uid

) t where allmoney>200

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