当数据库为空时，MySQL COUNT 查询返回行

Question

我这样做的方式有问题吗，因为我清空了数据库表来测试这段代码，它为 $cc_rows 返回值“1”...

$ccquerycount = "SELECT COUNT(*) FROM payments_cc_info WHERE user_id=$userid";
                $ccresult = mysql_query($ccquerycount) or die(mysql_error());
                $cc_rows = mysql_num_rows($ccresult);

                echo $cc_rows;

                if ($cc_rows > 0) {
                echo '<div class="message_success" align="center">Credit Card info on file.<br />Edit settings to change.</div>';
                } else {
                echo '<div class="message_error" align="center">No Credit Card info on file.<br />Edit settings to change.</div>';
                }

Answer 1

您将得到一行，一列，该列的值为零。

您需要执行 SELECT * FROM payments_cc_info WHERE user_id=$userid 并计算那里的行数，或者获取 COUNT(*) 的值并检查它.