下面是我想要做的： - 我需要一个函数，当作为参数的ID（为一个类的东西）将提供所有子类别和子子类别和子子sub..etc通过。 - 我想用递归函数，因为我不知道子类别的数量及其子子等 所以这里是我一直试图做的，到目前为止

Here is what I'm trying to do: - i need a function that when passed as an argument an ID (for a category of things) will provide all the subcategories and the sub-sub categories and sub-sub-sub..etc. - i was thinking to use a recursive function since i don't know the number of subcategories their sub-subcategories and so on so here is what i've tried to do so far

function categoryChild($id) {

    $s = "SELECT * FROM PLD_CATEGORY WHERE PARENT_ID = $id";
    $r = mysql_query($s);

    if(mysql_num_rows($r) > 0) {

        while($row = mysql_fetch_array($r))
            echo $row['ID'].",".categoryChild($row['ID']);
    }
    else {
        $row = mysql_fetch_array($r);
        return $row['ID'];
    }
}

如果我使用返回，而不是回应，我不会得到相同的结果。我为了解决这个问题，或者从头开始重写它需要一些帮助

If i use return instead of echo, i won't get the same result. I need some help in order to fix this or rewrite it from scratch

推荐答案

我有一个困难时期试图找出你的函数。我认为这会做你想要什么。它得到的ID为$ ID的类别所有的孩子，以及他们的孩子（从而获得整个子类别，你想，子子类别的效果）。

I had a hard time trying to figure out your function. I think this will do what you want. It gets all the children of a category with ID $id, and also their children (thus getting the whole sub category, sub sub category effect that you wanted).

function categoryChild($id) {
    $s = "SELECT ID FROM PLD_CATEGORY WHERE PARENT_ID = $id";
    $r = mysql_query($s);

    $children = array();

    if(mysql_num_rows($r) > 0) {
        # It has children, let's get them.
        while($row = mysql_fetch_array($r)) {
            # Add the child to the list of children, and get its subchildren
            $children[$row['ID']] = categoryChild($row['ID']);
        }
    }

    return $children;
}

这个函数将返回：

$var = array(
        'categoryChild ID' => array(
                'subcategoryChild ID' => array(
                        'subcategoryChild child 1' => array(),
                        'subcategoryChild child 2' => array()
                )
        ),
        'anotherCategoryChild ID' => array() # This child has no children of its own
);

它基本上返回与孩子的ID和包含其子项的ID的数组的数组。我希望这是任何帮助。

It basically returns an array with the ID of the child and an array containing the IDs of its children. I hope this is of any help.