public function dateIndaysoff($mydate=false){
        if(!$mydate)return false;

        $host = "localhost";
        $user = "user";
        $pass = "pass";
        $databaseName = "database";
        $tableName = "table";
        $con = mysql_connect($host,$user,$pass);
        $dbs = mysql_select_db($databaseName, $con);

       // $db=JFactory::getDbo();
        $dbs->setQuery("select date from table WHERE `date`='$mydate'")->query();
        return (int) $db->loadResult();
    }

if (dateIndaysoff(val)) {something}