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Thread: mysqli_query()/mysqli_num_rows()

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  1. #1
    Join Date
    Mar 2013
    Posts
    13

    mysqli_query()/mysqli_num_rows()

    I am receiving 2 error messages when testing my web page.

    Warning: mysqli_query() expects parameter 1 to be mysqli, null given in /home/content/41/10881941/html/guitarworld/media/pages/shoppingcart.php on line 117

    Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, null given in /home/content/41/10881941/html/guitarworld/media/pages/shoppingcart.php on line 117

    Here is my source code:

    PHP Code:
    <?php
    session_start
    ();
    ?>
    <?php
    $con
    =mysqli_connect("hostname","username","password","database");
    // Check connection
    if (mysqli_connect_errno())
      {
      echo 
    "<script type='text/javascript'>alert('Failed to connect to MySQL: ')</script>" mysqli_connect_error();
      }
    ?>

    <!DOCTYPE HTML>
    <html>
    <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <title>Guitar Shop | Shopping Cart</title>
    <link href="../css/style.css" rel="stylesheet" type="text/css">
    <link rel="shortcut icon" href="../images/favicon.ico" type="image/vnd.microsoft.icon" />
    <link rel="icon" href="../images/favicon.ico" type="image/vnd.microsoft.icon" />
    </head>

    <body>
    <div id="container">
      <header>
        <div id="logo"></div>
        <nav>
          <ul>
            <li><a href="../../index.php">Home</a> </li>
            <li><a href="guitars.php">Guitars</a>
              <ul>
                <li><a href="electric.php">Electric</a> </li>
                <li><a href="acoustic.php">Acoustic</a> </li>
              </ul>
            </li>
            <li><a href="register.php">Register</a> </li>
          </ul>
        </nav>
      </header>
      <div id="content1_shoppingcart">
        <h1>Shopping Cart</h1>
      </div>
      <div id="content2_shoppingcart">

      <?php
        $con
    =mysqli_connect("hostname","username","password","database");
        
    // Check connection
        
    if (mysqli_connect_errno())
          {
          echo 
    "<script type='text/javascript'>alert('Failed to connect to MySQL: ')</script>" mysqli_connect_error();
          }
        
    $id $_GET[id]; 
        
    $action $_GET[action]; 

        
    // If the ID doesn't exist, exit the script and display message
        
    if($id && !productExists($id)) {
            exit(
    "<p>An error occurred</p>");
        }

        switch(
    $action) {
            
    // Add
            
    case "add":
                
    $_SESSION['shoppingcart'][$id]++;
            break;
            
    // Remove
            
    case "remove":
                
    $_SESSION['shoppingcart'][$id]--;
                if(
    $_SESSION['shoppingcart'][$id] == 0) unset($_SESSION['shoppingcart'][$id]);
            break;
            
    // Empty
            
    case "empty":
                unset(
    $_SESSION['shoppingcart']);
            break;
        }
        
    ?>
        <?php
            $con
    =mysqli_connect("hostname","username","password","database");
            
    // Check connection
            
    if (mysqli_connect_errno())
              {
              echo 
    "<script type='text/javascript'>alert('Failed to connect to MySQL: ')</script>" mysqli_connect_error();
              }
            if(
    $_SESSION['shoppingcart']) {
                echo 
    "<table border=\"1\" padding=\"3\" width=\"40%\">";
                    foreach(
    $_SESSION['shoppingcart'] as $id => $quantity) {    
                            
    $sql sprintf($con,"SELECT name, description, price FROM electric WHERE id = %d;",$id); 
                            
    $result mysqli_query($con,$sql);
                            if(
    mysqli_num_rows($con,$result) > 0) {
                                list(
    $name$description$price) = mysqli_fetch_row($con,$result);
                                
    $line_cost $price $quantity;
                                
    $total $total $line_cost;
                                echo 
    "<tr>";
                                echo 
    "<td align=\"center\">$name</td>";
                                echo 
    "<td align=\"center\">$quantity <a href=\"$_SERVER[PHP_SELF]?action=remove&id=$id\">Remove</a></td>";
                                echo 
    "<td align=\"center\">$line_cost</td>";
                                echo 
    "</tr>";
                            }
            }
        echo 
    "<tr>";
        echo 
    "<td colspan=\"2\" align=\"right\">Total</td>";
        echo 
    "<td align=\"right\">$total</td>";
        echo 
    "</tr>";
        
        echo 
    "<tr>";
        echo 
    "<td colspan=\"3\" align=\"right\"><a href=\"$_SERVER[PHP_SELF]?action=empty\" onclick=\"return confirm('Are you sure?');\">Empty Shopping Cart</a>            </td>";
        echo 
    "</tr>";        
        echo 
    "</table>";
        }
        else {
            echo 
    "<p>You have no items in your shopping cart.</p>";
        }
        
        function 
    productExists($id) {
            
    $sql sprintf($con,"SELECT * FROM electric WHERE id = %d;",$id); 
            return 
    mysqli_num_rows(mysqli_query($con,$sql)) > 0;
        }
        
    ?>
        <p><a href="guitars.php">Continue Shopping</a></p>
        <?php
        ?>
      </div>
      <footer> <em>&copy;2011 | Guitar Shop </em> </footer>
    </div>
    </body>
    </html>
    Any help or ideas would be greatly appreciated folks!
    Last edited by NogDog; 12-27-2013 at 12:29 AM. Reason: put all code into one set of php tags

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