How to get information in jquery function from the php file - php

Question

My question is how to get an db information (in my case points just a number) from the php file to the jquery ajax script so here is my jquery:
function rate_down(id) {
var id = id;
//submit data to php script
var data = {
"id": id,
};
$.ajax({
type: "POST",
url: "rating.php",
data: data,
success: function(response) {
var currentValue = /* here i want to put the db number */
var newValue = +currentValue - 1;
$("#points_"+id).text(newValue);
},
error: function(jqXHR, textStatus, errorThrown){
alert(errorThrown);
}
});
};
And I want my raiting.php. I'm not sure if I should post it because its useless but here is my mysql query in raiting.php:
$pic_id = (int) $_REQUEST['id'];
mysql_query = mysql_query"SELECT points FROM `photos` WHERE `id` = '$pic_id'";

Answer 1

Problem is in your php script. Please dont use mysql_query. Use PDO.
$pic_id = (int) $_REQUEST['id'];
$db = new PDO("...");
$q = $db->prepare("SELECT points FROM `photos` WHERE `id` = :pic_id");
$q->bindValue(':pic_id', $pic_id);
$q->execute();
if ($q->rowCount() > 0){
$check = $q->fetch(PDO::FETCH_ASSOC);
$points = $check['points'];
}else{
$points = 0;
}
echo $points;
And then in your ajax function:
$.ajax({
type: "POST",
url: "rating.php",
data: data,
success: function(response) {
if(response != 0) {
var currentValue = response;
var newValue = +currentValue - 1;
$("#points_"+id).text(newValue);
}
},
error: function(jqXHR, textStatus, errorThrown){
alert(errorThrown);
}
});