ORacle外部应用与group by的组合

Question

为什么这两个查询有两个不同的结果：

1. 第一个查询：

        select c.customer_id, oo.order_id
          from co.CUSTOMERS c
         outer apply (select *
                        from co.orders o
                       where o.customer_id = c.CUSTOMER_ID
                       order by o.order_id desc fetch first 1 rows only) oo
         where c.CUSTOMER_ID = 22
           and oo.order_id = 10000

1. 第二次查询：

        select c.customer_id, oo.order_id
          from co.CUSTOMERS c
         outer apply (select *
                        from co.orders o
                       where o.customer_id = c.CUSTOMER_ID
                       order by o.order_id desc fetch first 1 rows only) oo
         where c.CUSTOMER_ID = 22
           and oo.order_id = 10000
         group by c.customer_id, oo.order_id

co.CUSTOMERS c 的数据

select * from co.CUSTOMERS c   where c.customer_id=22   

CUSTOMER_ID	EMAIL_ADDRESS	FULL_NAME
22	raymond.bailey@internalmail	Raymond Bailey

co.orders的数据

select * from co.orders o where o.customer_id=22
order by o.order_id  desc 

ORDER_ID	ORDER_DATETIME	CUSTOMER_ID	ORDER_STATUS	STORE_ID
1819	11-MAR-19 07.20.17.942291 AM	22	COMPLETE	22
1435	07-JAN-19 03.57.14.316173 PM	22	COMPLETE	1
511	19-JUL-18 06.24.36.024192 AM	22	COMPLETE	1
184	26-APR-18 05.13.15.426435 AM	22	COMPLETE	1

第一个查询不返回任何内容
但是第二个查询返回如下：

CUSTOMER_ID	ORDER_ID
22	10000

Answer 1

这是一个错误。我已经为你提出了这个问题。