如何显示分层的“嵌套集"?数据与PHP? [英] How to display hierarchical "NESTED SET" data with PHP?
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问题描述
我试图弄清楚如何使用php显示嵌套的MySQL数据.我设法搁置了所有的叶子节点",但后来我陷入了困境.我需要显示一棵完整的树及其所有元素的关系. 这是桌子
I'm trying to figure out how to display nested MySQL data using php. I've managed to set aside all the "leaf nodes" but then I got stucked. I need to display a whole tree and all of it's element's relations. Here's the table
category_id, name, lft, rgt
1 Saws 1 12
2 Chainsaws 2 7
3 Red 3 4
4 Yellow 5 6
5 Circular saws 8 9
6 Other saws 10 11
这是代码:
$query = 'SELECT node.name, node.lft, node.rgt
FROM item_cats AS node,
item_cats AS parent
WHERE node.lft BETWEEN parent.lft AND parent.rgt AND parent.name = "' . SAWS . '"
ORDER BY node.lft';
$result = mysql_query($query, $db) or die (mysql_error($db));
while ($row = mysql_fetch_assoc($result)) {
if ($row['rgt'] == $row['lft']+1) {
echo '==>';
}
echo $row['lft'];
echo $row['name'];
echo $row['rgt'];
echo '<br />';
echo '<br />';
}
这就是我得到的:
1Saws12
2Chainsaws7
==>3Red4
==>5Yellow6
==>8Circular saws9
==>10Other saws11
推荐答案
基于Stu向我显示的链接,本教程显示了用于确定深度的查询:
Based on the link Stu showed me, the tutorial shows this query for determining depth:
SELECT node.name, (COUNT(parent.name) - 1) AS depth
FROM nested_category AS node,
nested_category AS parent
WHERE node.lft BETWEEN parent.lft AND parent.rgt
GROUP BY node.name
ORDER BY node.lft
所以这样的事情应该起作用:
So something like this should work:
<?PHP
$query = 'SELECT node.name, (COUNT(parent.name) - 1) AS depth
FROM nested_category AS node,
nested_category AS parent
WHERE node.lft BETWEEN parent.lft AND parent.rgt
GROUP BY node.name
ORDER BY node.lft';
$result = mysql_query($query, $db) or die (mysql_error($db));
while ($row = mysql_fetch_assoc($result)) {
for ($i = 0; $i < $row['depth']; $i++) {
echo '==>';
}
echo $row['name'];
echo '<br />';
echo '<br />';
}
?>
这应该输出:
Saws
==>Chainsaws
==>==>Red
==>==>Yellow
==>Circular Saws
==>Other Saws
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