使用WHERE x IN选择语句(SELECT ...)

Question

我有两张桌子:

[ product_to_category
---------------------
product_id
category_id


[ category
---------------------
category_id
parent_id

我需要使用category.parent_id为'39'来获取所有product_id.这就是我正在尝试的东西,但是当它至少有几百个时它会返回空白:

SELECT
product_id
FROM
product_to_category
WHERE
category_id IN (
SELECT parent_id FROM category WHERE parent_id = '39'
)

我在这里想做的可能吗？

Answer 1

得到它了:

SELECT product_id FROM product_to_category INNER JOIN类别ON product_to_category.category_id = category.category_id AND category.parent_id = 39