Select 关系数据库的最低价格

Question

我正在尝试 select 列出每个产品的价格可能最低的产品列表。为了说明上下文，我有这些 tables:

**tb_product**
id | product | active | image | description
1  | shoes A |    1   | ...   | ...
2  | shirt C |    1   | ...   | ...
4  | pants E |    1   | ...   | ...
---

**tb_store**
id | name    | phone
11 | Store X | ...
22 | Store F | ...
33 | Store K | ...
---

**tb_product_store** 
id_product | id_store | price
1          | 11       | 9.90
1          | 22       | 12.90
2          | 11       | 15.90
2          | 33       | 12.90
4          | 33       | 22.90
---

例如，我想 select table tb_product_store 上列出的所有产品的价格最低，所以结果将是这样的：

id_product | product | price
1          | shoes A | 9.90
2          | shirt C | 12.90
4          | pants E | 22.90

我有这个查询：

SELECT 
    a.id, a.product,
    MIN(b.price) as 'price'

FROM tb_product a 
    JOIN tb_product_store b ON b.id_product = a.id

WHERE a.active = 1
ORDER BY a.product

但是这个查询 returns 只有一个产品的最低价格，而不是包含所有产品和最低价格的列表。

怎样才能得到预期的结果？

Answer 1

SELECT a.id, a.product,
   b.price as 'price'
FROM tb_product a 
join (select id_product, min(price)
       from tb_product_store group by id_product) b
     on b.id_product = a.id
whera a.active = 1
order by a.product

Select 关系数据库的最低价格

Select min price from relational database

mysql

relational-database