为什么返回true？

Question

I can't seem to find the problem.

// Check that someone from this IP didn't register a user within the last hour (DoS prevention)
$query = mysqli_query($dbc, "SELECT COUNT(id) FROM accounts WHERE registration_ip = '".$_SERVER['REMOTE_ADDR']."'  AND registered > ".(time() - 3600));

if (mysqli_num_rows($query) > 0) {
    $errors[] = 'To prevent registration flooding, at least an hour has to pass between registrations from the same IP. Sorry for the inconvenience.';
}

Why does this always return true no matter what? Even if the accounts table is empty.

Answer 1

如果我没记错的话，您的数据将始终为1行，表示计数值（因为您使用的是计数）。

Answer 2

Even there is 0 rows that match your condition, it'll simply return this.

+-----------+
| COUNT(id) |
+-----------+
|         0 |
+-----------+

Because you wanted the count of rows. Its 0 . Hence there is one row .

Here is how you should handle it.

$row = mysqli_fetch_row($query));
$count = intval($row[0]);
mysqli_free_result($query);

if ($count > 0)
....

Answer 3

You are checking the returned rows not the value. So check like that

$row = mysqli_fetch_row($query));
$count = $row[0];

if ($count > 0)
{

}