ratiing

<?php

require_once('config.php');
if($_SERVER['REQUEST_METHOD'] == "POST")
{
//Get the coupon parameters

$user_id = mysqli_real_escape_string($conn,$_POST['user_id']);

$coupon_id      = mysqli_real_escape_string($conn,$_POST['coupon_id']);

$rating    = mysqli_real_escape_string($conn,$_POST['rating']);


$getRating="SELECT meta_value FROM wp_postmeta WHERE post_id='$coupon_id' AND meta_key='ratings_average'";
$cpnReatingqry=$conn->query($getRating);

$cpnRatingRes=$cpnReatingqry->fetch_assoc();
$couponRat=$cpnRatingRes["meta_value"];
if(!empty($couponRat))
{
$prevRating=$couponRat;
$currentRating=$rating;


$getRatingUser="SELECT meta_value FROM wp_postmeta WHERE post_id='$coupon_id' AND meta_key='ratings_users'";
$cpnReatinguserqry=$conn->query($getRatingUser);

$cpnRatinguserRes=$cpnReatinguserqry->fetch_assoc();
$couponRatusers=$cpnRatinguserRes["meta_value"];

$totaluser=$couponRatusers+1;

$totalRating=$prevRating+$currentRating;

$couponAvgrate=$totalRating/$totaluser;


$updateRating="UPDATE wp_postmeta SET meta_value='$couponAvgrate'
WHERE post_id='$coupon_id' AND meta_key='ratings_average'";

$udatepost_res = $conn->query($updateRating);

$updateRatuser="UPDATE wp_postmeta SET meta_value='$totaluser'
WHERE post_id='$coupon_id' AND meta_key='ratings_users'";

$udaterateuser_res = $conn->query($updateRatuser);


}
else
{

$totaluser=1;

$couponAvgrate=$rating;

$insert_post="INSERT INTO wp_postmeta (post_id,meta_key,meta_value)
VALUES($coupon_id ,'ratings_average','$couponAvgrate')";

$insertpost_res = $conn->query($insert_post);

$insert_rateuser="INSERT INTO wp_postmeta (post_id,meta_key,meta_value)
VALUES($coupon_id ,'ratings_users','$totaluser')";

$insertrateuser_res = $conn->query($insert_rateuser);





}





$responce['responce_msg']='Thank you for your rating';

echo json_encode($responce);


}
else
{

$json = array("msg" => "Request method not accepted");

echo json_encode($json);

}


?>