Just in case someone else needs this in the future:
PHP Code:
$user = $DB_site->query_first("
SELECT userid, username, avatarrevision
FROM " . TABLE_PREFIX . "user
WHERE userid = $userid
");
$DB_site->query("
UPDATE " . TABLE_PREFIX . "post
SET username = '" . addslashes($user['username']) . "',
userid = 0
WHERE userid = $userid
");
$DB_site->query("
UPDATE " . TABLE_PREFIX . "usernote
SET username = '" . addslashes($user['username']) . "',
posterid = 0
WHERE posterid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "usernote
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "user
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "userfield
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "usertextfield
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "access
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "event
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "customavatar
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "customprofilepic
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "moderator
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "subscribeforum
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "subscribethread
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "subscriptionlog
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "session
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "userban
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "administrator
WHERE userid = $userid
");
$DB_site->query("
DELETE FROM " . TABLE_PREFIX . "usergrouprequest
WHERE userid = $userid
");
$DB_site->query("DELETE FROM " . TABLE_PREFIX . "pmreceipt WHERE userid = $userid");
$DB_site->query("DELETE FROM " . TABLE_PREFIX . "pm WHERE userid = $userid");