php - invalid MySQL argument in mysql_fetch_array -

warning: mysql_fetch_array(): supplied argument not valid mysql result resource in /rideanddrive/_classes/__base.php on line 45

my code :

public static function selectspecific($obj, $data_base, $cond) {     self::$query = "select $obj " . self::$baseprefix . "$data_base $cond";     $out = self::execute();     $array = mysql_fetch_array($out); // line warning line     return $array[$obj]; } 

execute function, if needed :

private static function execute()  {     $out = mysql_query(self::$query);     return $out; } 

code's works fine. don't warning on localhost (running wamp, might have turned them off ?), works on live server, i'm getting above warning, how correct warning gone ?

on selectspecific function embed if check see execute function returning proper resource result .. if not echo sql run on server separately if can find error if there error sql ,here updated function if embedded

public static function selectspecific($obj, $data_base, $cond)     {         self::$query = "select $obj " . self::$baseprefix . "$data_base $cond";         $out = self::execute();         if($out){           $array = mysql_fetch_array($out); // line warning line           return $array[$obj];        }else {          return false;        }     }