Question

我有一种情况，我希望从customer表中返回null值，并且相当于bill表中Bill代码的select distinct。

我该怎么做？

表客户

ID
Name
CustNumber
BILLCODE

表格

ID
BILLCODE

我正在尝试做类似

的事情

Select Null ID, Null NAME, Null CUSTNUMBER
from CUSTOMER
RIGHT JOIN ID, BILLCODE 
on customer.billcode = bill.billcode

我只希望表格中的每个账单代码都有1条记录。

Answer 1

with billcodes as (select distinct billcode from bill)
select b.billcode, c.id, c.name, c.custnumber
from billcodes b
left outer join customer c on c.billcode=b.billcode

或者：

select b.billcode, c.id, c.name, c.custnumber
from (select distinct billcode from bill) b
left outer join customer c on c.billcode=b.billcode

Answer 2

我猜这个问题是：如何从客户表中返回所有客户的每个账单代码清单？

如果是，您要使用group by和left outer join：

select b.billcode, c.id, c.name, c.custnumber
from customer c left outer join
     bill b
     on c.billcode = b.billcode
group by b.billcode, c.id, c.name, c.custnumber

NULL＆amp;在oracle中有所区别

2 个答案: