php - 需要 mysql 查询帮助 - 按父级分组

Question

我正在尝试执行一个 mysql 查询，该查询将创建一个父项数组，其子项位于其下方。但我不是 100% 确定如何。这是我到目前为止所做的:

从类别中选择 * 作为 rf ORDER BY 父项，名称 ASC

这是输出的内容(数组):

Array
(
    [0] => stdClass Object
        (
            [id] => 7
            [name] => Safety Clothing
            [parent] => 0
        )

    [1] => stdClass Object
        (
            [id] => 8
            [name] => Safety Footwear
            [parent] => 0
        )

    [2] => stdClass Object
        (
            [id] => 9
            [name] => Workwear
            [parent] => 0
        )

    [3] => stdClass Object
        (
            [id] => 4
            [name] => Polos
            [parent] => 7
        )

    [4] => stdClass Object
        (
            [id] => 3
            [name] => Shirts
            [parent] => 7
        )

    [5] => stdClass Object
        (
            [id] => 6
            [name] => Jackets
            [parent] => 9
        )

    [6] => stdClass Object
        (
            [id] => 1
            [name] => Pants
            [parent] => 9
        )

    [7] => stdClass Object
        (
            [id] => 2
            [name] => Shirts
            [parent] => 9
        )

    [8] => stdClass Object
        (
            [id] => 5
            [name] => Shorts
            [parent] => 9
        )

)

正如您所看到的，子项具有父项的 id(父项设置为 0)，但我不确定如何将它们合并在一起以执行类似这样的数组:

父级

-- child

-- child

父级

父级

-- child

-- child

-- child

如有任何帮助，我们将不胜感激:)

Answer 1

还有

选择父级，GROUP_CONCAT(name) 作为名称 FROM 类别作为 rf GROUP BY 1;

您将为每个父项获取一行，其中父项 ID 位于第一列，子项名称在第二列中以逗号分隔。