嘗試從數據庫中檢索數據時發生mysql_fetch_array（）錯誤

Question

我正在做一個總結購物車，試用我自己的教程。 但我遇到了一些錯誤。

有人說， 「警告：mysql_fetch_array（）預計參數1是資源，布爾在C中給出：\ XXX \ XXX \ XXX \ XXX \ XXX \ xxx.php第18行」

我想以顯示我已購買的物品，所以我從購物車數據庫中傳回物品。 （使用Dreamweaver工具，我只需拖放它）。 但是，項目不顯示，但它給了我這個錯誤，而不是。

我可以知道我的代碼有什麼問題，把SQL注入放在一邊（因爲我沒有使用它，仍然嘗試基本）。

<?php require_once('Connections/MyDatabase.php'); ?> 
<?php 
session_start(); 
?> 

<?php 
$cartTotal = 0; 
if(isset($_POST['CheckoutBTN'])) 
{ 
    date_default_timezone_set('Asia/Singapore'); 
    $time=date('D,F j, Y, H:i:s A'); 
    $uname = $_SESSION['MM_Username']; 
foreach ($_SESSION["supermarketcart"] as $each_item) 
    { 

    $item_id = $each_item['item_id']; 
     $sql = mysql_query("SELECT * FROM supermarket WHERE id = '$item_id' LIMIT 1"); 
     while($row = mysql_fetch_array($sql)){ 
    $productdes = $row['description']; 
    $price = number_format($row['price'],2); 
    $size = $row['packaging']; 
    $itemqty = $each_item['quantity']; 

    $pricetotal = $price * $each_item['quantity']; 
    $cartTotal = number_format($pricetotal + $cartTotal,2); 

    $checkout="INSERT INTO supermarketcart (itemid, productdes, package, itemprice, qty, username, ddate) VALUES 
          ('$item_id', '$productdes', '$size', '$price','$itemqty','$uname','$time')"; 
    mysql_query($checkout)or die(mysql_error()); 

     } 
    } 
} 

?> 
<?php 
//initialize the session 
if (!isset($_SESSION)) { 
    session_start(); 
} 

// ** Logout the current user. ** 
$logoutAction = $_SERVER['PHP_SELF']."?doLogout=true"; 
if ((isset($_SERVER['QUERY_STRING'])) && ($_SERVER['QUERY_STRING'] != "")){ 
    $logoutAction .="&". htmlentities($_SERVER['QUERY_STRING']); 
} 

if ((isset($_GET['doLogout'])) &&($_GET['doLogout']=="true")){ 
    //to fully log out a visitor we need to clear the session varialbles 
    $_SESSION['MM_Username'] = NULL; 
    $_SESSION['MM_UserGroup'] = NULL; 
    $_SESSION['PrevUrl'] = NULL; 
    unset($_SESSION['MM_Username']); 
    unset($_SESSION['MM_UserGroup']); 
    unset($_SESSION['PrevUrl']); 

    $logoutGoTo = "login.php"; 
    if ($logoutGoTo) { 
    header("Location: $logoutGoTo"); 
    exit; 
    } 
} 
?> 
<?php 
if (!function_exists("GetSQLValueString")) { 
function GetSQLValueString($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "") 
{ 
    if (PHP_VERSION < 6) { 
    $theValue = get_magic_quotes_gpc() ? stripslashes($theValue) : $theValue; 
    } 

    $theValue = function_exists("mysql_real_escape_string") ? mysql_real_escape_string($theValue) : mysql_escape_string($theValue); 

    switch ($theType) { 
    case "text": 
     $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL"; 
     break;  
    case "long": 
    case "int": 
     $theValue = ($theValue != "") ? intval($theValue) : "NULL"; 
     break; 
    case "double": 
     $theValue = ($theValue != "") ? doubleval($theValue) : "NULL"; 
     break; 
    case "date": 
     $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL"; 
     break; 
    case "defined": 
     $theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue; 
     break; 
    } 
    return $theValue; 
} 
} 

$colname_cart = "-1"; 
if (isset($_SESSION['MM_USERNAME'])) { 
    $colname_cart = $_SESSION['MM_USERNAME']; 
} 
mysql_select_db($database_MyDatabase, $MyDatabase); 
$query_cart = sprintf("SELECT * FROM supermarketcart WHERE username = %s", GetSQLValueString($colname_cart, "text")); 
$cart = mysql_query($query_cart, $MyDatabase) or die(mysql_error()); 
$row_cart = mysql_fetch_assoc($cart); 
$totalRows_cart = mysql_num_rows($cart); 

mysql_select_db($database_MyDatabase, $MyDatabase); 
$query_user_info = "SELECT * FROM user_data"; 
$user_info = mysql_query($query_user_info, $MyDatabase) or die(mysql_error()); 
$row_user_info = mysql_fetch_assoc($user_info); 
$totalRows_user_info = mysql_num_rows($user_info); 
?> 

Answer 1

按照您的代碼段，$each_item['item_id']不會被檢查，如果它設置了內部的東西。隨後的查詢有時會失敗（如果WHERE接近是空的SQL失敗）

$sql = mysql_query("SELECT * FROM supermarket WHERE id = '$item_id' LIMIT 1"); 

所以$sql將被設置爲false，你會得到你的錯誤之後。

所以你不要從遠程MySQL或有關未設置$each_item['item_id']

更改錯誤報告級別和調試的信息之後，您可能禁用警告消息：要做到這一點，之後添加此session_start();

error_reporting(E_ALL);