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POGetting a modified preorder tree traversal model (nested set) into a <ul>
 

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  1. POGetting a modified preorder tree traversal model (nested set) into a <ul>
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    <p>I am trying to get my data which is hierarchically set up with a tree traversal model into an &lt; ul> in order to show on my site. </p> <p>Here is my code:</p> <pre><code>function getCats($) { // retrieve all children of $parent $query = "SELECT max(rght) as max from t_categories"; $row = C_DB::fetchSingleRow($query); $max = $row["max"]; $result ="&lt;ul&gt;"; $query = "SELECT * from t_categories where lft &gt;=0 and rght &lt;= $max"; if($rs = C_DB::fetchRecordset($query)){ $p_right =""; $p_left =""; $p_diff=""; while($row = C_DB::fetchRow($rs)){ $diff = $row["rght"] -$row["lft"]; if($diff == $p_diff){ $result.= "&lt;li&gt;".$row['title']."&lt;/li&gt;"; }elseif (($row["rght"] - $row["lft"] &gt; 1) &amp;&amp; ($row["rght"] &gt; $p_right)){ $result. "&lt;ul&gt;"; $result.= "&lt;li&gt;".$row['title']."&lt;/li&gt;"; }else{ $result.= "&lt;li&gt;".$row['title']."&lt;/li&gt;"; } $p_right = $row["rght"]; $p_left = $row["lft"]; $p_diff = $diff; } } $result.= "&lt;/ul&gt;"; return $result; } </code></pre> <p>Here is my sample table:</p> <pre><code>|ID | TITLE | lft| rght | |1 | Cat 1 | 1 | 16 | |18 | Cat 2 | 3 | 4 | |22 | Cat 3 | 5 | 6 | |28 | Cat 4 | 7 | 8 | |34 | Cat 5 | 9 | 9 | |46 | Cat 6 | 11 | 10 | |47 | Cat 7 | 13 | 12 | |49 | Cat 8 | 15 | 14 | </code></pre> <p>Now it outputs something like:</p> <pre><code> &lt;ul&gt; &lt;li&gt;Cat 1&lt;/li&gt; &lt;li&gt;Cat 2&lt;/li&gt; &lt;li&gt;Cat 3&lt;/li&gt; &lt;li&gt;Cat 4&lt;/li&gt; &lt;li&gt;Cat 5&lt;/li&gt; &lt;li&gt;Cat 6&lt;/li&gt; &lt;li&gt;Cat 7&lt;/li&gt; &lt;li&gt;Cat 8&lt;/li&gt; &lt;/ul&gt; </code></pre> <p>Can anyone tell me why or how it will output the list in hierarchical a structure?</p> <p><a href="https://stackoverflow.com/questions/1300567/php-infinite-loop/1300599#1300599">Related topic</a></p>
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    1. COAre your columns named `links` and `rechts`, or `lft` and `right`? And does your code reflect what you actually have?
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    2. COsorry fixed it. I had to translate my code from dutch ;-)
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    3. COout of topic: for many reasons I suggest you to write your code only in english. This is a good habit!
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