WPMU A+ allow one appointment per day

allow one appointment per day.php

<?php
// Works only if login required
function limit_active_apps( $reply_array ) {
	global $wpdb, $current_user, $appointments;
	// Change statuses as required. i.e. remove pending condition if you wish
	$count = $wpdb->get_var( "SELECT COUNT(*) FROM " . $appointments->app_table . " WHERE user=".$current_user->ID." AND (status='pending' OR status='confirmed' OR status='paid' ) and created > DATE_SUB(CURDATE(), INTERVAL 1 DAY)" );
	if ( $count >= 3)
		return array( 'error'=>'You have reached maximum allowed number of appointments' );
	return $reply_array;
}
add_filter( 'app_pre_confirmation_reply', 'limit_active_apps' );