Q: SQL select of users by metadata Hi I'm trying to select users  with a particular role only, using the following sql statement...
SELECT DISTINCT ID, u.user_login, u.user_nicename, u.user_email
FROM wp_users u, wp_usermeta m
WHERE m.meta_key = 'wp_capabilities'
AND m.meta_value LIKE '%supplier%'
ORDER BY u.user_registered

However, it reurns the whole table. What am I doing wrong?
PS this needs to be a SQL select as I'm doing this in myphpadmin to export the data to csv.
Thanks in advance!

A: Double-check your SQL syntax.  It sounds like you want to do a JOIN ... But you're not building the query correctly.
It should be something more like:
SELECT u.ID, u.user_login, u.user_nicename, u.user_email
FROM $wpdb->users u
INNER JOIN $wpdb->usermeta m ON m.user_id = u.ID
WHERE m.meta_key = 'wp_capabilities'
AND m.meta_value LIKE '%supplier%'
ORDER BY u.user_registered

You have to tell the query how you're relating the user meta to the user.
Also note that I'm using $wpdb-> rather than wp_.  This is important if you ever expect to use this query in a plugin on a site with a database prefix other than "wp."  If you're running things directly in SQL, though, you should switch back.

A: There's a (query-)class built into core: 
new WP_User_Query;
// Example
$all_subscribers = new WP_User_Query( array( 'role' => 'subscriber' ) );

This then allows looping through the user objects:
// Example
foreach ( $all_subscribers as $subscriber )
{
    echo $subscriber->display_name;

    // Check object:
    var_dump( $subscriber );
}

For further examples, or querying users by other fields, please consult the codex.
