关于sql 多表联合查询方法很多,我们今天就来讲一下关于sql多表查询的用法与实例代码,一般会用到select * from (select ) union 来操作。
select 类型,sum(合计金额) from
(select 商品名称,数量,日期,类型,合计金额 from 出库表
where 日期 > '2010-5-5 00:00:00'
union
select 商品名称,数量,日期,类型,合计金额 from 入库表
where 日期 > '2010-5-5 00:00:00'
union
select 商品名称,数量,日期,类型,合计金额 from 销售表
where 日期 > '2010-5-5 00:00:00')
group by 类型
下面来看看实例
三个表
收费表
id flowid totall
1 k1 3000
详细表
id flowid pid num
1 k1 1 2000
2 k1 2 1000
付款方式表
id pname
1 现金
2 支票
3 刷卡
create table pay(id int,flowid varchar(10),totall int)
insert into pay select 1,'k1',3000
create table detail(id int,flowid varchar(10),pid int,num int)
insert into detail select 1,'k1',1,2000
insert into detail select 2,'k1',2,1000
create table mode(id int,pname varchar(10))
insert into mode select 1,'现金'
insert into mode select 2,'支票'
insert into mode select 3,'刷卡'
declare @sql varchar(8000)
set @sql=''select @sql=@sql+',['+pname+']=sum(case b.pid when '+rtrim(id)+' then num else 0 end)'
from modeset @sql='select a.id,a.flowid,a.totall'+@sql+' from pay a,detail b where a.flowid=b.flowid group by a.id,a.flowid,a.totall'
exec(@sql)
结果:
id flowid totall 现金 支票 刷卡
1 k1 3000 2000 1000 0