vinny42 Posted September 26, 2013 Share Posted September 26, 2013 One the one hand, the code can't look familiar because you are not using the method I'm using. On the otherhand, nothing will drop into #21 because your real problem isn't about building arrays. What you need to do, at the most basic level, is recursively climb the tree from the source node untill you run into node 144 or until there are no mode parent nodes. There are no arrays involved at all, forget arrays, they are not relevant here. Just write a function that can fetch a record, check if it has a parent. if no parent stop. if it has a parent then check if that parent is the node you need. if yes; stop, be happy. If not fetch the parentnode, check if it's parent is the 144 node, etc etc.. That's what my code does, in a class structure, but that's realy how you should be programming anyway, if you want to keep your code easy to maintain. Quote Link to comment https://forums.phpfreaks.com/topic/282407-query-hierarchy-in-reverse/page/2/#findComment-1451309 Share on other sites More sharing options...
Solution Barand Posted September 26, 2013 Solution Share Posted September 26, 2013 I had something like this in mind $db = new mysqli(HOST, USERNAME, PASSWORD, DATABASE); $fullSectionsArray = array(1,2,3,4,5,6,7,8,9,10); $parentId = 144; $descendants = array(); findDescendants($parentId, $descendants, $db); $descendedFrom144 = array_intersect($descendants, $fullSectionsArray); $notDescended = array_diff($fullSectionsArray, $descendants); function findDescendants($parentId, &$descendants, $db) { $res = $db->query("SELECT category_id FROM category WHERE parent = $parentId"); while ($row = $res->fetch_assoc()) { $descendants[] = $row['category_id']; findDescendants($row['category_id'], $descendants, $db); } } Quote Link to comment https://forums.phpfreaks.com/topic/282407-query-hierarchy-in-reverse/page/2/#findComment-1451327 Share on other sites More sharing options...
John_A Posted September 27, 2013 Author Share Posted September 27, 2013 (edited) Thanks very much for everyone's input. I think I've got what I need with this: - <?php $targetsection=144; $fullSectionsArray = array(1,1505,1507,1509,1510,1511); $editedSectionsArray = array(); $invertedSectionsArray = array(); $pathsArray = array(); foreach ($fullSectionsArray as &$theSection) { $thispath = get_my_path($theSection); $pathsArray[$theSection] = $thispath; } foreach( $pathsArray as $mKey => &$mVal ) { if( in_array($targetsection, $mVal ) ) { $editedSectionsArray[] = $mKey; } else { $invertedSectionsArray[] = $mKey; } } // $node is the name of the node we want the path of function get_my_path($node) { global $tableSections; // look up the parent of this node $query = "SELECT parent FROM $tableSections WHERE sectionID = " . $node; $result = mysql_query($query); $record = mysql_fetch_assoc($result); // save the path in this array $myPath = array(); // only continue if this $node isn't the root node (that's the node with no parent) if ($record['parent'] != '' && $record['parent'] != '0' && $record['parent'] != '1') { // the last part of the path to $node, is the name // of the parent of $node $myPath[] = $record['parent']; // we should add the path to the parent of this node to the path $myPath = array_merge(get_my_path($record['parent']), $myPath); } // return the result return $myPath; } ?> vinny42 - while I don't doubt your code works and is perhaps the better approach, I start with an array in, and need two arrays out the other end (the template system of the 3rd party application in use expects arrays) and, although I said earlier I don't care about the intermediate path nodes, at some point I might like to list the full paths of all filtered descendants rather than just the immediate parent sections and so the get_my_path function is handy for this. Barand - yours looks a lot more like what I was expecting. I haven't tested it but don't see why it wouldn't work. I may well end up switching to this if I decide I really don't care about full paths! Again, thanks to all for their input Edited September 27, 2013 by John_A Quote Link to comment https://forums.phpfreaks.com/topic/282407-query-hierarchy-in-reverse/page/2/#findComment-1451361 Share on other sites More sharing options...
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