php - 如何将 mysql_num_rows 等函数更改为 mysqli？

Question

当我将我的PHP文件发布到免费的虚拟主机站点时，我遇到了一个错误。出现的错误如下：

下面是我的项目的代码。

    $sql= "SELECT * FROM user WHERE staff_id='$staff_id' AND password='$password'";
    $query = mysql_query($sql) or die("Error: " . mysql_error());  //this is error on line 42
    $row = mysql_num_rows($query);

我不确定错误是什么，因为我是自学 PHP 的。希望你们能指出我应该做些什么改变。提前致谢！

标签： phphtmlmysqldreamweaver

Answer 1

    $sql= "SELECT * FROM user WHERE staff_id='$staff_id' AND password='$password'";
$query = mysql_query($sql) or die("Error: " . mysql_error());  //this is error on line 42
$row = mysql_num_rows($query);

试试这个

$sql= "SELECT * FROM user WHERE staff_id='$staff_id' AND password='$password'";
$query = mysqli_query($con, $sql) or die("Error: " . mysqli_error($con)); // $con is the connection to database like  // $con = mysqli_connect("localhost","my_user","my_password","my_db");
$row = mysqli_num_rows($query);