Question

我只是在mysql中加入了连接和诸如此类的东西。我有一个小问题我正在努力，我想根据他们所属的促销活动返回产品和相应客户/公司的最低价格。我能够获得产品，公司和价格，但我无法获得最低价格。

当前输出如下：

select G.promotionid, name, startdate, enddate, issuer, company_name, productid, 
promotionprice from promotion_general G inner join company_promotions C on G.promotionid =
C.promotionid inner join productpromotions P on G.promotionid = P.promotionid order by
company_name, productid;
+-------------+------------+------------+------------+----------------+------------------------+-----------+----------------+
| promotionid | name       | startdate  | enddate    | issuer         | company_name           | productid | promotionprice |
+-------------+------------+------------+------------+----------------+------------------------+-----------+----------------+
|           3 | promo2     | 2014-05-08 | 2014-06-08 | zakiir         | Company C              | DEMOB     |         300.00 |
|           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost | Company F              | DEMOA     |         500.00 |
|           3 | promo2     | 2014-05-08 | 2014-06-08 | zakiir         | Company F              | DEMOB     |         300.00 |
|           2 | promo2     | 2014-08-08 | 2014-09-08 | zakiir         | Company F              | DEMOB     |         650.00 |
|           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost | Company F              | DEMOB     |         600.00 |
|           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost | Company F              | DEMOC     |         650.00 |
|           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost | Company G              | DEMOA     |         500.00 |
|           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost | Company G              | DEMOB     |         600.00 |
|           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost | Company G              | DEMOC     |         650.00 |
+-------------+------------+------------+------------+----------------+------------------------+-----------+----------------+

组件表如下所示：

 select * from productpromotions;
+-------------+-----------+----------------+---------------------+
| promotionid | productid | promotionprice | productdateset      |
+-------------+-----------+----------------+---------------------+
|           1 | DEMOA     |         500.00 | 2014-08-07 10:54:07 |
|           1 | DEMOB     |         600.00 | 2014-08-07 00:02:03 |
|           2 | DEMOB     |         650.00 | 2014-08-07 00:02:03 |
|           1 | DEMOC     |         650.00 | 2014-08-07 00:02:07 |
|           3 | DEMOB     |         300.00 | 2014-08-07 00:02:03 |
+-------------+-----------+----------------+---------------------+

和

select * from company_products;
ERROR 1146 (42S02): Table 'afl_discounts.company_products' doesn't exist
mysql> select * from company_promotions;
+-------------+------------------------+
| promotionid | company_name           |
+-------------+------------------------+
|           1 | Company G              |
|           2 | Company F              |
|           3 | Company C              |
|           1 | Company F              |
|           3 | Company F              |
+-------------+------------------------+

和

select * from promotion_general;
+-------------+------------+------------+------------+----------------+
| promotionid | name       | startdate  | enddate    | issuer         |
+-------------+------------+------------+------------+----------------+
|           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost |
|           2 | promo2     | 2014-08-08 | 2014-09-08 | zakiir         |
|           3 | promo2     | 2014-05-08 | 2014-06-08 | zakiir         |
|           4 | promo3     | 2014-05-08 | 2014-06-08 | zakiir         |
+-------------+------------+------------+------------+----------------+

我需要做些什么来使我的输出看起来像这样？

+-------------+------------+------------+------------+----------------+------------------------+-----------+----------------+
| promotionid | name       | startdate  | enddate    | issuer         | company_name           | productid | promotionprice |
+-------------+------------+------------+------------+----------------+------------------------+-----------+----------------+
 |           3 | promo2     | 2014-05-08 | 2014-06-08 | zakiir         | Company C             | DEMOB     |         300.00 |
 |           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost | Company F             | DEMOA     |         500.00 |
 |           3 | promo2     | 2014-05-08 | 2014-06-08 | zakiir         | Company F             | DEMOB     |         300.00 |
 |           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost | Company F             | DEMOC     |         650.00 |
 |           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost | Company G             | DEMOA     |         500.00 |
 |           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost | Company G             | DEMOB     |         600.00 |
 |           1 | test promo | 2014-07-08 | 2014-08-08 | root@localhost | Company G             | DEMOC     |         650.00 |
+-------------+------------+------------+------------+----------------+------------------------+-----------+----------------+

如果已删除DEMO B的重复且更昂贵的价格。

我知道它很长，但我很难过。

谢谢，

Answer 1

尝试运行此..我认为它会做你想要的。

SELECT 
    * 
FROM
(   SELECT 
        cp.promotionid, 
        name, 
        startdate, 
        enddate, 
        issuer, 
        company_name, 
        p.productid, 
        p.promotionprice 
    FROM company_promotions cp
    JOIN productpromotions p ON p.promotionid = cp.promotionid
    JOIN promotion_general pg ON pg.promotionid = cp.promotionid
    ORDER BY cp.promotionid DESC
) t 
GROUP BY company_name, productid

DEMO

从连接表形成的行返回字段的最小值

1 个答案: