Shopping cart in php (mysql_num_rows)

Question

I am trying to do a shopping cart in php.

I am getting the following error

"Warning: mysql_num_rows() expects parameter 1 to be resource, string given in C:\\wamp\\www\\shoppingCart\\cart.php on line 19" and its returning there is no products.

The error in the code is in line 19:

if(mysql_num_rows($get)==0)[
<?php
  session_start();
  $page='index.php';
  $server="localhost";
  $username="root";
  $password="";
  $database="jennifer_db";
  $conn = new mysqli($server, $username, $password, $database);

  if($conn->connect_error){
    die("Connection failed: " .$conn->Connect_error);
  }

  function products(){
    $get='mysql_query("select Product_ID, Product_name, Product_desc,
        Product_price from products where quantity>0 order by id desc")';

    if(mysql_num_rows($get)== 0){
      echo "There ae no products to display!";
    }
    else{
    echo "Success!";
    }
  }
?>

Answer 1

You are mixing mysqli and mysql functions. Please use mysqli or PDO

Answer 2

I made some modifications in your code (I used mysqli), I think it should work, check out the comments:

session_start();

$page = 'index.php';
$server = 'localhost';
$username = 'root';
$password = '';
$database = 'jennifer_db';

// this is the connection object
$mysqli = new mysqli($server, $username, $password, $database);

// if we have an error we abort
if ($mysqli->connect_errno)
  die('Connection failed: ' . $mysqli->connect_error);


function products(&$conn)
{
    // we pass $conn to this function and make the query
    // note that only the SQL query string should be in ""
    $result = $conn->query("select Product_ID, Product_name, Product_desc, Product_price from products where quantity > 0 order by id desc");

    if ($result)
    {
        // checking row count
        echo (!$result->num_rows ? 'There are no products to display!' : 'Success');

        // we close the result set
        $result->close();
    }
    else 
        echo "Error: {$conn->error}";
}

// call products() here
products($mysqli);

// we close the connection
$conn->close();

For further info about mysqli check http://php.net/manual/en/book.mysqli.php

also check out PDO and decide which one you want to use (mysqli or PDO) http://php.net/manual/en/book.pdo.php

I think you can learn from this too: http://davidwalsh.name/php-shorthand-if-else-ternary-operators

Hope I helped. :)