vb.org Archive - Randomizing Numbers (the hard way)

Hi -- I'm trying to finish up a script that will pull user ids from a table and assign random ids from the same table to them -- like this:

1 -- 5
2 -- 3
3 -- 2
4 -- 1
5 -- 4

The trick is that a number can't be assigned to itself and it can't be assigned twice. Here is the code I have. It probably doesn't make sense to you, but hopefully you can figure out where I need to patch it up to make it randomize correctly. Right now it's not assigning numbers to themselves, but it is assigning numbers more than once. Thanks for any help you can give!

PHP Code:


		
			
// ###################### Assign #######################

if ($_REQUEST['do'] == 'assign') { 

    echo "<table>";

    $qry = $db->query_read("SELECT * FROM {$tbl_main} ORDER BY userid ASC");

    $totalsantas = mysql_num_rows($qry);



    while ($uinfo = $db->fetch_array($qry))

    {

    $get_from = $uinfo['get_from'];

    $give_to = $uinfo['give_to'];

    $uid = $uinfo['userid'];

    $qry2 = $db->query_first("SELECT * FROM " . TABLE_PREFIX . "user WHERE userid = $uid");

    $uname_from = $qry2['username'];

    $qry_r = $db->query_first("SELECT * FROM {$tbl_main} ORDER BY RAND()");

    $uid2 = $qry_r['userid'];

    $get_from2 = $qry_r['get_from'];



    if (!$get_from = $get_from2 AND !$uid = $uid2){

        

    $db->query_write ("UPDATE {$tbl_main} SET give_to='$give_to',get_from='$get_from' WHERE userid='$uid'");





    $qry3 = $db->query_first("SELECT * FROM " . TABLE_PREFIX . "user WHERE userid = $uid2");

    $uname_to = $qry3['username'];

    

    

    

    echo "

            <tr>

                <td>$uname_from&nbsp;($uid) is assigned to $uname_to&nbsp;($uid2) as Secret Santa.<td>

            </tr>



                    ";

    }

    }

    echo "

            <tr>

                <td>Total Santas: $totalsantas<td>

            </tr>

            </table>

        ";    



}

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Template Usage: (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (1)bbcode_php_printable (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_navbar_search (1)printthread (1)printthreadbit (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit showthread	Included Files: ./printthread.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/class_bbcode_alt.php ./includes/class_bbcode.php ./includes/functions_bigthree.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete printthread_start bbcode_fetch_tags bbcode_create bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete printthread_post printthread_complete
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(1)ad_header_logo
(1)ad_navbar_below
(1)bbcode_php_printable
(1)footer
(1)gobutton
(1)header
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(6)option
(1)post_thanks_navbar_search
(1)printthread
(1)printthreadbit
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global
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./printthread.php
./global.php
./includes/init.php
./includes/class_core.php
./includes/config.php
./includes/functions.php
./includes/class_hook.php
./includes/modsystem_functions.php
./includes/class_bbcode_alt.php
./includes/class_bbcode.php
./includes/functions_bigthree.php

Hooks Called:

init_startup
init_startup_session_setup_start
init_startup_session_setup_complete
cache_permissions
fetch_threadinfo_query
fetch_threadinfo
fetch_foruminfo
style_fetch
cache_templates
global_start
parse_templates
global_setup_complete
printthread_start
bbcode_fetch_tags
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X vBulletin 3.8.12 by vBS Debug Information
Page Generation 0.01139 seconds Memory Usage 1,727KB Queries Executed 10 (?)
More Information
Template Usage: (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (1)bbcode_php_printable (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_navbar_search (1)printthread (1)printthreadbit (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit showthread	Included Files: ./printthread.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/class_bbcode_alt.php ./includes/class_bbcode.php ./includes/functions_bigthree.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete printthread_start bbcode_fetch_tags bbcode_create bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete printthread_post printthread_complete
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