รบกวนสอบถามเกี่ยวกับ การวนลูปเพื่อส่งเมล์หน่อยครับใน php

for ($i = 0; $i < $total_reciver; $i++) {
		
		$strTo = $std_email[$i];
		//echo $i. " " .$strTo." " .$std_fname[$i]. $std_lname[$i];
        $strSubject = "=?UTF-8?B?" . base64_encode($non_type . "จาก IST Notify") . "?=";
        $strHeader .= "MIME-Version: 1.0' . \r\n";
        $strHeader .= "Content-type: text/html; charset=utf-8\r\n";
        $strHeader .= "From:IST Notify <[email protected]>";

        $strMessage = "ยินดีต้อนรับ " . $std_fname[$i] . " " . $std_lname[$i] . "<br>";
        $strMessage .= "คุณได้รับการแจ้งเตือนจากคุณ " . $sender_fname . " " . $sender_lname;
        $strMessage .= "<br> โดยมีรายละเอียดดังนี้ <br> ";
        $strMessage .= $detail;
        $strMessage .= "<br>";
        $strMessage .= "<br><br> ============================= <br><br>";
        $strMessage .= "ขอบคุณที่ใช้บริการ ";

        $flgSend = @mail($strTo, $strSubject, $strMessage, $strHeader);
        if ($flgSend) {
            $sql_receiver = "INSERT INTO `receiver`(`student_id`,`notification_id`) VALUES ('" . $std_id[$i] . "', '" . $non_id . "'); ";
            $sqlQrr = mysql_query($sql_receiver);
            
            if ($sqlQrr) {
                $data["msg"] = "yes : " . $sql_receiver;
                $send++;
            } else {
                $data["msg"] = "not : " . $sql_receiver;
            }
        } else {
            $data["msg"] = "ไม่สำเร็จ";
            $fail++;
        }
           sleep(10);
    }

for ($i = 0; $i < $total_reciver; $i++) {
		
		$strTo = $std_email[$i];
		//echo $i. " " .$strTo." " .$std_fname[$i]. $std_lname[$i];
        $strSubject = "=?UTF-8?B?" . base64_encode($non_type . "จาก IST Notify") . "?=";
        $strHeader .= "MIME-Version: 1.0' . \r\n";
        $strHeader .= "Content-type: text/html; charset=utf-8\r\n";
        $strHeader .= "From:IST Notify <[email protected]>";

        $strMessage = "สวัสดีค่ะ  " . $std_fname[$i] . " " . $std_lname[$i] . "<br>";
        $strMessage .= " คุณได้รับการแจ้งเตือนจากคุณ  " . $sender_fname . " " . $sender_lname . "โดยเนื้อหาจะเกี่ยวกับ " . $target ." ค่ะ ";
        $strMessage .= "<br> โดยมีรายละเอียดดังนี้ <br> ";
        $strMessage .= $detail;
        $strMessage .= "<br>";
        $strMessage .= "<br><br> ============================= <br><br>";
        $strMessage .= "ขอบคุณที่ใช้บริการ ";

		$mail = new PHPMailer();
		$user = "=?UTF-8?B?" . base64_encode($std_fname[$i] . " " . $std_lname[$i]) . "?=";
		$mail -> AddAddress($std_email[$i], $user );
		$mail -> Subject = $strSubject;
		$mail -> MsgHTML($strMessage);
		$mail -> SetFrom('[email protected]', 'IST Notify');
		
		if (!$mail -> Send()) {
			//echo "Mail Error: " . $mail -> ErrorInfo;
			$fail++;
		} else {
			//echo "Mail Sent";
			$send++;
			$sql_receiver = "INSERT INTO `receiver`(`student_id`,`notification_id`) VALUES ('" . $std_id[$i] . "', '" . $non_id . "'); ";   
			$sqlQrr = mysql_query($sql_receiver);
            if ($sqlQrr) {
               // $data["msg"] = "yes : " . $sql_receiver;
                
            } else {
               // $data["msg"] = "not : " . $sql_receiver;
            }
		}
    }