php - 检查产品是否已购买

Question

您好，我的网站有 1 个问题，我不知道该怎么处理这部分。我需要检查该产品是否已购买。因此，如果用户登录并购买了该商品，与未购买该商品相比，它会显示其他内容。

使用此示例数据

products
productID, title, runTime, imageLarge, classification
1, noah, 128 minutes, noahLarge.jpg, M
2, left behind, 105 minutes, leftBehindLarge.jpg, MA 15+
3, green lantern, 133 minutes, greenLantern.jpg, M

invoice
invoiceID, memberID, purchaseDate
1,11,1/10/2014
2,13,15/10/2014


productsinvoice
invoiceID, productID
1, 2
1, 3
2, 1
2, 2

members
memberID, username, pass, first name, last name
11, bob, fwofefef, bob, marley
13, prius, f334ff43f, eski, martey

问题出在我的 SQL 查询和这里的这段代码

$sql = "SELECT productID, title, price, imageSmall, imageLarge FROM products WHERE releaseDATE < NOW() ORDER BY releaseDate DESC LIMIT 0,4";
    $result = mysqli_query($con, $sql) or die(mysqli_error($con)); //run the query
    while ($row = mysqli_fetch_array($result))
{
     if(!isset($_SESSION['user']))
      {
      echo '
      <h4>$'. $row['price'] .'</h4>
      <p><input type="button" value="Add to Cart" onclick="addtocart(' .$row['productID'] . ')" class="btn btn-primary" value="Add to cart"/></p>';
      }
      else {
      echo '
      <a href="../pages/movieWatch.php?productID='.$row['productID'].'" class="btn btn-success"><span class="glyphicon glyphicon-cloud"> Stream</a>&nbsp;&nbsp;<a href="#" class="btn btn-info"><span class="glyphicon glyphicon-hdd"> Download</a>';
      }

}所以基本上，如果用户 bob 购买了 ProductID 2, 3 我希望它显示这 2 个产品的选项，但其余的仍然说添加到购物车并忽略 $_SESSION['user'] 只是确保 if 条件有效确实如此。

Answer 1

首先，您还应该从发票表中选择memberID。所以你的查询应该是:

SELECT productID, title, price, imageSmall, imageLarge, memberID FROM products JOIN productsinvoice ON productsinvoice.productID=products.productID JOIN invoice ON productsinvoice.invoiceID=invoice.invoiceID WHERE releaseDATE < NOW() ORDER BY releaseDate DESC LIMIT 0,4;

第二，假设您还在 session 变量中设置了 memberID，请在 if 语句中添加另一个条件:

if(!isset($_SESSION['user'])){
   if ($row['memberID'] != $_SESSION['user']['memberID']) {
      echo '
      <h4>$'. $row['price'] .'</h4>
      <p><input type="button" value="Add to Cart" onclick="addtocart(' .$row['productID'] . ')" class="btn btn-primary" value="Add to cart"/></p>';
   }
} else {
  echo '
  <a href="../pages/movieWatch.php?productID='.$row['productID'].'" class="btn btn-success"><span class="glyphicon glyphicon-cloud"> Stream</a>&nbsp;&nbsp;<a href="#" class="btn btn-info"><span class="glyphicon glyphicon-hdd"> Download</a>';
}