Where和Order By子句不起作用

Question

所以這段代碼不起作用，我無法弄清楚。

$productid = (isset($_REQUEST['productId'])) ? $_REQUEST['productId'] : ''; 

$query = "SELECT * FROM products WHERE productId = '$productid' ORDER BY rand() limit 3"; 

Answer 1

也許嘗試：

$productid = (isset($_REQUEST['productId'])) ? $_REQUEST['productId'] : ''; 
if ($productid != ''){ 
    $query = "SELECT * FROM products WHERE productId = '$productid' ORDER BY rand() limit 3"; 
} else { 
    $query = "SELECT * FROM products ORDER BY rand() limit 3"; 
} 

這將返回所有的產品，如果產品ID沒有過來。