多表联接.sql

简单的sql语句 数据与汇总。 高手多多指点。

select * from suppliers
select * from products

select a.supplierid,companyname,sum(unitprice )
from suppliers as a
inner join products as b
on a.supplierid=b.supplierid

select * from orders
select * from customers

select distinct companyname
from orders as a
inner join customers as b
on a.customerid=b.customerid
where orderdate > 1/1/98
/* 内联接*/

select * from orders as a
full outer join customers as b
on a.customerid=b.customerid
/*完整外联接*/