compare number of items in the mysql row (php wordpress) - wordpress

Question

In my wordpress mockup, I have meta_value for users which is called ref_credit. This meta value for sandro looks like this:
174 1 ref_credit a:2:{i:0;s:1:"9";i:1;s:2:"10";}
Means he referred users with id=9,10
Another user meta_value looks like this:
209 9 ref_credit a:1:{i:0;s:2:"11";}
He referred only 1 user id=11.
Now I'd like to create a simple leader-board, I mocked up something but logics is completely wrong. I understand my code compares values and orders by this. I want to order it by number of users referred.
Any ideas?
complete function is this:
//get_users calls WP_User_Query and returns an array of matching users
$users = get_users(
array( 'fields' => 'all_with_meta',
'meta_query' => array( array( 'key' => 'ref_credit', // the meta field (or key) we want to target
'compare' => '>=' // comparison method (optional: =, >, <, etc)
)))
);
//custom function for comparing the data we want to sort by
function cmp($a, $b){
if ($a->points == $b->points) {
return 0;
}
return ($a->points > $b->points) ? -1 : 1;
}
//usort sorts our $users array with our function cmp()
usort($users, 'cmp');
//leaving an array of $users sorted by the value of meta 'points'
echo '<ol>';
foreach ($users as $user) {
echo '<li>' . $user->display_name . '</li>';
}
echo '</ol>';

Answer 1

I think there are a few problems.
The first is that all_with_meta doesn't seem to bring back the metadata, despite what the name implies. Not sure what it's supposed to do - the codex doesn't help much. So you'll have to grab the ref_credit values yourself.
Secondly, your comparison seems to be using something called points, not ref_credit. Not sure where that's coming from. Since ref_credit is an array, you'll have to compare the array lengths, not the values themselves (using count say).
Leaving your original query as is, something like this should work (though you may have to check I've got the cmp result the right way around):
//get_users calls WP_User_Query and returns an array of matching users
$users = get_users(
array( 'fields' => 'all_with_meta',
'meta_query' => array(
array( 'key' => 'ref_credit', // the meta field (or key) we want to target
'compare' => '>=' // comparison method (optional: =, >, <, etc)
)
)
)
);
foreach($users as $user_id => $user) {
$user->ref_credit = get_user_meta($user_id, 'ref_credit', true);
}
//custom function for comparing the data we want to sort by
function cmp($a, $b){
return count($b->ref_credit) - count($a->ref_credit);
}
usort($users, 'cmp');
//leaving an array of $users sorted by the value of meta 'points'
echo '<ol>';
foreach ($users as $user) {
echo '<li>' . $user->display_name . '</li>';
}
echo '</ol>';