Question

我有两张桌子：

类别

id - name - parent
1 - Category 1 - 0
2 - Category 2 - 0
3 - Category 3 - 0
4 - Category 4 - 0
5 - Subcategory 11 - 1
6 - Subcategory 111 - 5
7 - Subcategory 112 - 5
...

产品

id - name - category - description
1 - Name - 5 - Description

在类别表中，我有3个级别

第1类
- 子类别11
- 子类别111
- 子类别112
- 子类别113
子类别12
- 子类别121
- 子类别122
- 子类别123
- 子类别13
第2类
第3类

我从子类别中选择产品：

mysql_query("SELECT *, products.name AS p_name, categories.name AS c_name
FROM products
INNER JOIN categories ON categories.id = products.category
WHERE categories.id = '". $_GET['items'] ."'
GROUP BY products.id DESC");

产品属于第三级别类别（子类别111，子类别112，子类别113，子类别121 ...）

当我访问父类别或主要类别（类别1，类别2，子类别11，子类别12 ...）时，如何查看此类别中的所有产品？

谢谢！

Answer 1

如果知道或假设等级的级别数，您可以执行以下操作：

Select Root.name
    , Level1.name As Level1Category
    , Level2.name As Level2Category
From Category As Root
    Left Join Category As Level1
        On Level1.parent = Root.id
    Left Join Category As Level2
        On Level2.parent = Level1.id
Where Root.parent = 0
Order By Root.name, Level1.name, Level2.name

然后查看您只需将产品加入到层次结构的任何级别的产品：

Select Root.name
    , Level1.name As Level1Category
    , Level2.name As Level2Category
    , P.name As ProductName
From Category As Root
    Left Join Category As Level1
        On Level1.parent = Root.id
    Left Join Category As Level2
        On Level2.parent = Level1.id
    Join Products As P
        On P.category = Root.id
            Or P.category = Level1.id
            Or P.category = Level2.id
Where Root.parent = 0
Order By Root.name, Level1.name, Level2.name, P.name

列出主要类别和子类别的所有产品

1 个答案: