php - Get all child, grandchild etc nodes under parent using php with mysql query results

Question

I've been trying to figure this out but I haven't gotten anywhere.Hopefully someone can come to my rescue.

My problem is I'm using adjacency list data model to produce my hierarchy data in mysql.I can retrieve the table (see below) into a multidimension array with associative array for each item. What I want to do is once I get this array , I want to get another array with all the nodes (child, grandchild etc) under a parent id (including the parent item).I just can't workout how to code tihs in php.

In MySQL my table appears like this:

id     name       parent_id
1  Electronics          0
2  Televisions          1
3  Portable Electronics 1
4  Tube                 2
5  LCD                  2
6  Plasma               2
7  Mp3 Players          3
8  CD Players           3
9  2 Way Radios         3
10 Flash                7

I can retrive all rows with this code into an associative array with this.

$r = mysql_query("SELECT * FROM test ");
        $data = array();
        while($row = mysql_fetch_assoc($r)) {
         $data[] = $row;
         }

Gets Results:

Array 
( 
    [0] => Array 
    ( 
        [id] => 1 
        [name] => Electronics 
        [parent_id] => 0 
    ) 
    [1] => Array 
    ( 
        [id] => 2 
        [name] => Televisions 
        [parent_id] => 1 
    ) 
    [2] => Array 
    ( 
        [id] => 3 
        [name] => Portable Electronics 
        [parent_id] => 1 
    )
    [3] => Array 
    (
        [id] => 4 
        [name] => Tube 
        [parent_id] => 2 
    )
    [4] => Array 
    (
        [id] => 5 
        [name] => LCD 
        [parent_id] => 2
    )
    [5] => Array
    (
        [id] => 6 
        [name] => Plasma 
        [parent_id] => 2
    )
    [6] => Array
    (
        [id] => 7 
        [name] => Mp3 Players 
        [parent_id] => 3 
    )
    [7] => Array 
    (
        [id] => 8 
        [name] => CD Players 
        [parent_id] => 3
    )
    [8] => Array 
    (
        [id] => 9 
        [name] => 2 Way Radios 
        [parent_id] => 3
    )
    [9] => Array
    (
        [id] => 10 
        [name] => Flash 
        [parent_id] => 7 
    ) 
)

With those result I want to filter it down with an id.

Say for example I wanted an associative array of every node under Portable Electronics with the id of 3.(Use id for code)

It would return an array with rows with ids:

3 Portable Electronics (Selected parent has to be included)
7 Mp3 Players (Child)
8 CD Players (Child)
9 2 way Radios (Child)
10 Flash (Grand Child)

if Flash had children it would return those as well.

So the end result would return an array like the one above however only with those items.

Please note: I'm not after a function that creates a multidimension array of the tree structure (Already got a solution for that) .I want to build a function: fetch_recursive($id) which receives an ID and returns all the items in that level and in the levels below etc etc.

Hope this helps

Thanks in advance

score 19 · Accepted Answer

编辑：

我之前发布了一个解决方案，可以从您提供的输出中构建一个多维数组，以及一种id从该特定数组中获取特定元素的所有子元素的方法。我现在已经弄清楚如何直接从您的输出中检索子元素（无需先通过buildtree()函数：

function fetch_recursive($src_arr, $currentid, $parentfound = false, $cats = array())
{
    foreach($src_arr as $row)
    {
        if((!$parentfound && $row['id'] == $currentid) || $row['parent_id'] == $currentid)
        {
            $rowdata = array();
            foreach($row as $k => $v)
                $rowdata[$k] = $v;
            $cats[] = $rowdata;
            if($row['parent_id'] == $currentid)
                $cats = array_merge($cats, fetch_recursive($src_arr, $row['id'], true));
        }
    }
    return $cats;
}

要使用上面的函数，只需将输出数组传递$data给第一个参数，然后id您想从第二个参数中检索子元素：

前任。：

$list = fetch_recursive($data, 3);

哪个应该为您提供正确的数组结构id 3（如本答案最后一个代码框中的示例所示）。

原答案：

直到现在，我才开始编写递归函数来根据这种设计构建嵌套树。我敢肯定还有很多其他人写过类似的功能，但这个绝对适合你：

function buildtree($src_arr, $parent_id = 0, $tree = array())
{
    foreach($src_arr as $idx => $row)
    {
        if($row['parent_id'] == $parent_id)
        {
            foreach($row as $k => $v)
                $tree[$row['id']][$k] = $v;
            unset($src_arr[$idx]);
            $tree[$row['id']]['children'] = buildtree($src_arr, $row['id']);
        }
    }
    ksort($tree);
    return $tree;
}

该函数将递归地从邻接列表中构建一棵树，并保持 id 的升序排列。这也使得id每个父/子的 's 成为每个信息数组的键。

这段代码：

$r = mysql_query("SELECT * FROM test ");
$data = array();
while($row = mysql_fetch_assoc($r)) {
    $data[] = $row;
}
echo '<pre>';
print_r(buildtree($data));
echo '</pre>';

将输出如下内容：

要将特定的所有子节点id放到一维数组中，可以使用此函数：

function fetch_recursive($tree, $parent_id, $parentfound = false, $list = array())
{
    foreach($tree as $k => $v)
    {
        if($parentfound || $k == $parent_id)
        {
            $rowdata = array();
            foreach($v as $field => $value)
                if($field != 'children')
                    $rowdata[$field] = $value;
            $list[] = $rowdata;
            if($v['children'])
                $list = array_merge($list, fetch_recursive($v['children'], $parent_id, true));
        }
        elseif($v['children'])
            $list = array_merge($list, fetch_recursive($v['children'], $parent_id));
    }
    return $list;
}

基于上面的buildtree()函数，假设我们想要获取id3 的所有子节点：

echo '<pre>';
print_r(fetch_recursive(buildtree($a), 3));
echo '</pre>';

这将输出：

Array
(
    [0] => Array
        (
            [id] => 3
            [name] => Portable Electronics
            [parent_id] => 1
        )

    [1] => Array
        (
            [id] => 7
            [name] => Mp3 Players
            [parent_id] => 3
        )

    [2] => Array
        (
            [id] => 10
            [name] => Flash
            [parent_id] => 7
        )

    [3] => Array
        (
            [id] => 8
            [name] => CD Players
            [parent_id] => 3
        )

    [4] => Array
        (
            [id] => 9
            [name] => 2 Way Radios
            [parent_id] => 3
        )

)

score 0 · Accepted Answer

这是一种让您更进一步的方法，您可以决定如何构建结果数组以及选择包含哪些字段。这未经测试，但您应该看到逻辑。

// connect to db

// set id counter
$ids = 0;

// declare array
$categories = new Array();

// determine max ids
$query = mysql_query("SELECT COUNT(1) AS ids FROM test");
$result = mysql_fetch_array(query); // get result
$count = $result['ids'];

// loop through ids for parents
for($ids = 0; $ids <= $count; $ids++) {
  $query1 = mysql_query("SELECT * FROM test WHERE id = '" . $ids . "'");
  $query2 = mysql_query("SELECT id, name, parent_id FROM test WHERE parent_id = '" . $ids . "'");
  // check if has children
  if(mysql_num_rows($query2) > 0) {
    // iterate through children and add to array
    while (mysql_fetch_array($query2) as $row) {
      $categories[$ids]['child'][$row['id']] = $row['name'];
    }
  }
  // check if has siblings
  if(mysql_num_rows($query1) > 0) {
    // iterate through children and add to array
    while (mysql_fetch_array($query2) as $row) {
      $categories[$ids]['sibling'][$row['id']] = $row['name'];
    }
  }
}

php - Get all child, grandchild etc nodes under parent using php with mysql query results

2 回答 2

编辑：

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