php - 如何在php中获取父亲的名字

Question

我有一个示例代码:

products(id, parent_id, name)
1 | 0 | product1
2 | 0 | product2
3 | 1 | product1_1
4 | 1 | product1_2
5 | 2 | product2_1
6 | 2 | product2_2

并查询:

SELECT prod.id, prod.name
FROM `products` AS prod
INNER JOIN `products` AS prod_parent ON prod_parent.product_id = prod.parent_id

但结果是:

3 | product1_1
4 | product1_2
5 | product2_1
6 | product2_2

如何获取 parent 的父亲

 1 | product1
 2 | product2

Answer 1

在您的 SELECT 列表中具体说明您希望它们来自哪个表。这将为您提供所有四列，但您可以将其修剪为仅需要的列。

SELECT 
  prod.id AS prod_id,
  prod.name AS prod_name,
  prod.parent_id AS parent_id,
  prod_parent.name AS parent_name
FROM `products` AS prod
LEFT JOIN `products` AS prod_parent ON prod_parent.product_id = prod.parent_id