mysql 多表运算的问题

我用的MYsql 具体函数有一点点出入：而且你的表名建的太刺激了，都是in、out、return等关键字，我在表名上都添加了一个数字1，即 in1,out1,back1,return1,transfer1:

select

in1id,

in1amount -

if(in1id in(select `inId` from out1), (select sum(out1`amount`) from out1 where out1inId=in1id),0) +

if(in1id in(select out1`inId` from out1,back1 where out1id=back1outId), (select sum(back1`amount`) from back1,out1 where out1inId=in1id and out1id=back1outId),0) -

if(in1id in(select `inId` from transfer1),(select sum(transfer1`amount`) from transfer1 where in1id=transfer1inId),0)-

if(in1id in(select `inId` from return1), (select sum(return1`amount`) from return1 where return1inId=in1id),0) as total

from in1

经过测试后结果为：

id， total

1 490

2 486

3 489

希望能对你有所帮助

两张表如果是关联表，比如第一个表的sid对应第二个表的sid

用

select

from

表名1

a(a是表明的别名)

left

join

表名2

b

on

asid=bsid

;

如果没有关联

select

from

表1

,表2

你可以试试下面这个：

select from table as a inner (join) table_2 as b on (ach=bch) inner (join) table_3 as c on (cch=bch) inner (join) table_4 as d on (dch =cch) inner (join) table_5 as e on (ech = dch) inner (join) table_6 as f on (fch =ech) inner (join) table_7 as g on (gch=fch) inner (join) table_8 as h on (hch=gch) inner (join) table_9 as i on (ich =hch);

其实这个sql的查询命令你可以用一个循环来做，将字符串搞好就可以了。

以上就是关于mysql 多表运算的问题全部的内容，包括:mysql 多表运算的问题、mysql怎么多表查询两张不同的数据库表呢、MySQL多表查询（超过10个相关的表）等相关内容解答，如果想了解更多相关内容，可以关注我们，你们的支持是我们更新的动力！