Bind_param()问题；

Question

好的一天，我不太熟悉PHP，当我试图执行我的查询时，我会收到这个错误。

警告：

警告: mysqli_stmt::bind_param()：变量数与第10行/Users/site/userpanel.php . line中准备好的语句中的参数数不匹配

代码：

$query="SELECT SUM(gebruiker_id) AS totalitems FROM inventory WHERE gebruiker_id = 1";
$stmt = $db->prepare($query);
$stmt->bind_param("s", $items);
$stmt->execute();
$result = $stmt->bind_result($col1);

提前感谢！

Answer 1

您必须使用这样的占位符：

$query="SELECT SUM(gebruiker_id) AS totalitems FROM inventory WHERE gebruiker_id = ?";
$stmt = $db->prepare($query);
$stmt->bind_param("s", $items);
$stmt->execute();
$result = $stmt->bind_result($col1);

Answer 2

有时，您不需要绑定：

$query="SELECT SUM(gebruiker_id) AS totalitems FROM inventory WHERE gebruiker_id = 1";
$stmt = $db->prepare($query);
//$stmt->bind_param("s", $items);
$stmt->execute();
$result = $stmt->bind_result($col1);

或

$query="SELECT SUM(gebruiker_id) AS totalitems FROM inventory WHERE gebruiker_id = 1";
$stmt = $db->query($query);
$result = $stmt->bind_result($col1);

但是，如果您试图将$items绑定到gebruiker_id，那么请遵循@rizier123的答案。