category_product
---------------
id_category
id_product
product
---------------
id_product
id_manufacturer
manufacturer
---------------
id_manufacturer
name
当id_category等于某个值时,我如何创建一个SQL查询,以便它选择制造商中的所有名称?
发布于 2010-08-15 16:05:39
这是一个简单的表的内部连接:
SELECT m.name, cp.id_category
FROM manufacturer as m
INNER JOIN product as p
ON m.id_manufacturer = p.id_manufacturer
INNER JOIN category_product as cp
ON p.id_product = cp.id_product
WHERE cp.id_category = 'some value'
发布于 2010-08-15 16:09:29
没有连接的查询将如下所示:
SELECT m.name
FROM manufacturer as m, product as p, category_product as cp
WHERE cp.id_category = <your value>
AND cp.id_product = p.id_product
AND p.id_manufacturer = m.id_manufacturer
发布于 2010-08-15 16:14:09
Select M.name
From manufacturer M
Where M.id_manufacturer in ( Select P.id_manufacturer
From product P
Where P.id_product in ( Select C.id_product
From category_product C
Where C.id_category = ?))
https://stackoverflow.com/questions/3486644
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