[英]Get all child, grandchild etc nodes under parent using php with mysql query results
我一直試圖解決這個問題,但我沒有到達任何地方。希望有人可以來救我。
我的問題是我使用鄰接列表數據模型在mysql中生成我的層次結構數據。我可以將表(見下文)檢索到一個多維數組中,每個項目都有一個關聯數組。 我想要做的是,一旦我得到這個數組,我想得到另一個數組,包含父ID(包括父項)下的所有節點(子,孫等)。我只是無法鍛煉如何編碼tihs in PHP。
在MySQL中,我的表格如下所示:
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
我可以使用此代碼將所有行檢索到關聯數組中。
$r = mysql_query("SELECT * FROM test ");
$data = array();
while($row = mysql_fetch_assoc($r)) {
$data[] = $row;
}
獲取結果:
Array
(
[0] => Array
(
[id] => 1
[name] => Electronics
[parent_id] => 0
)
[1] => Array
(
[id] => 2
[name] => Televisions
[parent_id] => 1
)
[2] => Array
(
[id] => 3
[name] => Portable Electronics
[parent_id] => 1
)
[3] => Array
(
[id] => 4
[name] => Tube
[parent_id] => 2
)
[4] => Array
(
[id] => 5
[name] => LCD
[parent_id] => 2
)
[5] => Array
(
[id] => 6
[name] => Plasma
[parent_id] => 2
)
[6] => Array
(
[id] => 7
[name] => Mp3 Players
[parent_id] => 3
)
[7] => Array
(
[id] => 8
[name] => CD Players
[parent_id] => 3
)
[8] => Array
(
[id] => 9
[name] => 2 Way Radios
[parent_id] => 3
)
[9] => Array
(
[id] => 10
[name] => Flash
[parent_id] => 7
)
)
有了這些結果,我想用id過濾掉它。
比方說,我想要一個ID為3的便攜式電子設備下的每個節點的關聯數組。(代碼使用id)
它將返回一個包含id的行數組:
如果Flash有孩子,它也會返回。
因此最終結果將返回一個類似上面的數組,但只返回那些項目。
請注意:我不是在創建樹結構的多維數組的函數之后(已經有了解決方案)。我想構建一個函數:fetch_recursive($ id),它接收一個ID並返回所有項目那個級別和等級以下等等。
希望這可以幫助
提前致謝
我之前發布過一個解決方案,用於根據您提供的輸出構建多維數組,以及一種從特定數組中獲取特定id
所有子元素的方法。 我現在已經想出如何直接從輸出中檢索子元素(無需首先通過buildtree()
函數:
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 $cats;
}
要使用上面的函數,只需將輸出數組$data
傳遞給第一個參數,並將要從第二個參數中檢索子元素的id
傳遞給:
例:
$list = fetch_recursive($data, 3);
哪個應該為id
3
提供正確的數組結構(如本答案的最后一個代碼框中的示例所示)。
原答案:
到目前為止,我從未編寫過遞歸函數來構建嵌套樹。 我確信有很多其他人都寫過類似的功能,但這個功能絕對適合你:
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;
}
此函數將以鄰接列表的形式遞歸構建樹,並按升序對id進行排序。 這也使得每個父/子的id
成為每個信息數組的關鍵。
這段代碼:
$r = mysql_query("SELECT * FROM test ");
$data = array();
while($row = mysql_fetch_assoc($r)) {
$data[] = $row;
}
echo '<pre>';
print_r(buildtree($data));
echo '</pre>';
會輸出這樣的東西:
Array
(
[1] => Array
(
[id] => 1
[name] => Electronics
[parent_id] => 0
[children] => Array
(
[2] => Array
(
[id] => 2
[name] => Televisions
[parent_id] => 1
[children] => Array
(
[4] => Array
(
[id] => 4
[name] => Tube
[parent_id] => 2
[children] => Array()
)
[5] => Array
(
[id] => 5
[name] => LCD
[parent_id] => 2
[children] => Array()
)
[6] => Array
(
[id] => 6
[name] => Plasma
[parent_id] => 2
[children] => Array()
)
)
)
[3] => Array
(
[id] => 3
[name] => Portable Electronics
[parent_id] => 1
[children] => Array
(
[7] => Array
(
[id] => 7
[name] => Mp3 Players
[parent_id] => 3
[children] => Array
(
[10] => Array
(
[id] => 10
[name] => Flash
[parent_id] => 7
[children] => Array()
)
)
)
[8] => Array
(
[id] => 8
[name] => CD Players
[parent_id] => 3
[children] => Array()
)
[9] => Array
(
[id] => 9
[name] => 2 Way Radios
[parent_id] => 3
[children] => Array()
)
)
)
)
)
)
要將特定id
所有子節點都放到一維數組上,可以使用此函數:
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 $list;
}
基於上面的buildtree()
函數,假設我們想要獲取id
3的所有子節點:
echo '<pre>';
print_r(fetch_recursive(buildtree($a), 3));
echo '</pre>';
這將輸出:
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
)
)
這是一種讓您更進一步的方法,您可以決定如何構建結果數組以及選擇包含哪些字段。 這沒有經過測試,但您應該看到邏輯。
// 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'];
}
}
}
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