Posted by Rik on 12/17/22 11:55

monomaniac21 wrote:
> hi all
>
> On a networking site i am working on each user has their own id and
> the id of another person who they are linked to. what i want to do is
> to be able to pull up a list of everyone linked to one person and all
> the ppl linked to them. So the query would work something like get id
> of linked get linked row get id of linked to this person get of
> person get id of linked to person.... this needs to go on until it
> reaches one person who is not linked to anybody. can anyone tell me
> how to achieve that with a control loop?

First of all, it's not clear to me what you want exactly. You want ALL
persons linked to one, but stop as soon as one of them is not linked to
anyone? This doesn't make sense to me, unless the structure is a clear tree,
with only 'big boss' not linked to anyone for each person in the table. A
bit of insight in your database structure would help.

If you've got a hierarchical tree, then maybe this site will give you some
insight:
http://dev.mysql.com/tech-resources/articles/hierarchical-data.html

If it's not that simple, a self_reference in PHP would almost certainly be
required.
Pseudo code (all I can do without a proper database explanation):

function get_persons($id){
global $database, $linked;
if( return false;
$persons = $database->users_linked($id);
if(!$persons) return false;
foreach($persons as $person){
$linked[] = $person;
if(get_person($person)===false) return false;
}
}
$linked = array();
get_persons($id);

Grtz,
--
Rik Wasmus

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