Oracle如何比較行？

Question

我有桌子。

SALESMAN_REGION
(
       SALESMAN_ID    INTEGER,
       REGION_ID      INTEGER
);

SALESMAN
(
       SALESMAN_ID    INTEGER,
       SALESMAN_NAME  VARCHAR2(50)       
);

TABLE SALES
(
       SALE_ID        INTEGER,
       PRODUCT_ID     INTEGER,
       SALESMAN_ID    INTEGER,
       YEAR           INTEGER,
       Quantity       INTEGER,
       PRICE          INTEGER
);       

而且我需要此信息，其中托尼的銷售額比凱文高。 我寫了這個查詢

 select s.region_id,sum(s.quantity),s.salesman_id from   sales s where s.salesman_id in (
select sr.salesman_id from salesman_region sr
inner join
salesman sm on sm.salesman_id = sr.salesman_id
where 
sm.salesman_name = 'Tony' or sm.salesman_name = 'Kevin') group by s.region_id ,s.salesman_id order by s.region_id;

輸出為：

REGION_ID   SUM(S.QUANTITY) SALESMAN_ID
1   10          1776             10
2   10          1603             30
3   20          1813             10
4   20          1479             30
5   30          1218             10
6   30          1516             30

但是我不知道如何比較這個或其他方式。 誰能幫我？

Answer 1

我將使用條件聚合來解決這個問題：

select s.region_id,
       sum(case when sm.salesman_name = 'Tony' then s.quantity else 0 end) as QTony,
       sum(case when sm.salesman_name = 'Kevin' then s.quantity else 0 end) as QKevin
from salesman_region sr inner join
     salesman sm
     on sm.salesman_id = sr.salesman_id inner join
     sales s
     on s.sales_man_id = sm.salesman_id
group by s.region_id
having (sum(case when sm.salesman_name = 'Tony' then s.quantity else 0 end) >
        sum(case when sm.salesman_name = 'Kevin' then s.quantity else 0 end) 
       )

注意：為使此方法有效，它假定推銷員僅在一個地區。 如果不是這樣，則您的數據結構無法回答您的問題，因為您不知道哪個銷售在哪個地區。