mysqli - How to free memory in php class method -

i present part of mine class works correctly.
want advice in:
how release resources $result->free() method in function , place them in code.

is useful write @ end of function, when return value before? when have placed before return operator, function doesn't work.

thanks in advance!

require_once 'ggc_config.php';  class ggc {             public static function executequery($querystring, &$id){         $mysqli = new mysqli(_ggc_host_ , _ggc_user_ , _ggc_password_ , _ggc_db_);             if (mysqli_connect_errno()) {             echo("connect failed: ". mysqli_connect_error());             return 0;             }//if          $mysqli->set_charset("utf8");         $result=$mysqli->query($querystring);              if ($result===true){             $id=$mysqli->insert_id;             return 1;             }//if             else{             return 0;             }//else         $result->free();         $mysqli->close();     }//executequeryi       public static function getresults($querystring){         $mysqli = new mysqli(_ggc_host_ , _ggc_user_ , _ggc_password_ , _ggc_db_);             if (mysqli_connect_errno()){             die("connect failed: ". mysqli_connect_error());             }//if         $mysqli->set_charset("utf8");              if ($result = $mysqli->query($querystring)){                 while ($row = $result->fetch_row()) {                     ($i=0; $i<$mysqli->field_count; $i++){                         $a[$i][]= $row[$i];                     }//for                 }//while                }//if            return $a;         $result->free();         $mysqli->close();        }//function   }//end of class 

due advicies have changet mine code this:

require_once 'ggc_config.php';

class ggc {            public static function executequery($querystring, &$id){         $mysqli = new mysqli(_ggc_host_ , _ggc_user_ , _ggc_password_ , _ggc_db_);         if (mysqli_connect_errno()) {             echo("connect failed: ". mysqli_connect_error());             unset($mysqli);             return 0;         }//if          $mysqli->set_charset("utf8");         $result=$mysqli->query($querystring);          if ($result===true){             $id=$mysqli->insert_id;             unset($result);             unset($mysqli);             return 1;         }//if         else{             unset($result);             unset($mysqli);             return 0;         }//else     }//executequery       public static function getresults($querystring){         $mysqli = new mysqli(_ggc_host_ , _ggc_user_ , _ggc_password_ , _ggc_db_);         if (mysqli_connect_errno()){             die("connect failed: ". mysqli_connect_error());         }//if         $mysqli->set_charset("utf8");          if ($result = $mysqli->query($querystring)){             while ($row = $result->fetch_row()) {                 ($i=0; $i<$mysqli->field_count; $i++){                     $a[$i][]= $row[$i];                 }//for             }//while            }//if            unset($result);         unset($mysqli);         return $a;     }//function   }//end of class 

update:

of course, way wrote somehow wrong. can not after return clause because end function execution. you'll need free result before returning.

the way wrote it, with:

$result->free(); $mysqli->close(); 

would work place return clause after that.

$result->free(); $mysqli->close(); return $a;