ajax data response always 0 in php mysql

Question

I want to load some data from mysql to a div via ajax php. The id field which is auto increment is always equal to zero.

I have tried using get, post etc but none is wor

Answer 1

I assume that customer_id is a unique key in your database and only one row is returned for each id in your database. So, how to correctly use PDO statements:

$sql = "SELECT * FROM customers WHERE customer_id=:id";
//Prepare your SELECT statement.
$statement = $pdo->prepare($sql);
//The Primary Key of the row that we want to select.
$id = intval($_REQUEST['customer_id']);
//I highly recomment not to use $_REQUEST, use $_GET or even better $_POST

//Bind our value to the paramater :id.
$statement->bindValue(':id', $id);

//Execute our SELECT statement.
$statement->execute();

//Fetch the row.
$row = $statement->fetch(PDO::FETCH_ASSOC);

//If $row is FALSE, then no row was returned.
if($row === false){
    echo $id . ' not found!';
} else{
    echo 'Found: ' . $row['first_name'];
}

EDIT Also, change your ajax request like this:

$.ajax({
  url: 'getCustomerDetails.php',
  type: 'POST',
  data: {customer_id:uid}
})

Answer 2

Start with debugging your actual result from the database.

if (isset($_REQUEST['customer_id'])) {

        $id = intval($_REQUEST['customer_id']);
        $query = "SELECT * FROM customers WHERE customer_id=:id";
        $stmt = $pdo->prepare( $query );
        $stmt->execute(array(':id'=>$id));
        $row=$stmt->setFetchMode(PDO::FETCH_ASSOC);

You are NOT checking for errors.

Two suggestions:

1) You are using <?php echo $row['first_name'];?>. If you inspected the resultset you could see what is wrong with that. Just output the result in the (wrongly named) $row variable with print_r() and the like. I am sure you will see what went wrong.

2) I strong advise AGAINST using $_REQUEST. It is lazy and errorprone. Do you know where the 'customer_id' came from? Session? Cookie? POST? Or Get? If you are passing information via GET => use GET