MySQL SQL 多对多选择
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时间：2020-08-31 16:52:08 来源:igfitidea点击:
SQL many to many select
提问by Ken
category_product
---------------
id_category
id_product
product
---------------
id_product
id_manufacturer
manufacturer
---------------
id_manufacturer
name
How would I create an SQL query so that it selects all the names from manufacturer when id_category is equal to something?
我将如何创建 SQL 查询，以便在 id_category 等于某值时从制造商中选择所有名称？
回答by chryss
It's a straightforward inner join of the tables:
这是表的直接内部联接：
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'
回答by YoK
Query without joins will look like following :
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
回答by CooL i3oY
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 = ?))
回答by Geri Croi
SELECT m.name, cp.id_category
FROM manufacturer AS M INNER JOIN product AS P
ON M.id_manufacturer = M.id_manufacturer
INNER JOIN category_product AS CP
ON P.id_product = CP.id_product
WHERE cp.id_category = 'add value'
回答by Adriaan Stander
Try something like
尝试类似的东西
SELECT m.*
FROM category_product cp INNER JOIN
product p ON cp.id_product = p.id_product INNER JOIN
manufacturer m ON p.id_manufacturer = m.id_manufacturer
WHERE cp.id_category = <your_value>
