错误：mysql_num_rows（）需要参数1

Question

I get error while trying to run this code:

        $sql = "SELECT * FROM user WHERE username = '$uname' AND password = '$password'";
        $result=mysql_query($sql);
        $num_row=mysql_num_rows($sql);
        $row=mysql_fetch_array($result);

The issue is with the line $num_row=mysql_num_rows($sql);

The error message is:

Warning: mysql_num_rows() expects parameter 1 to be resource, string given

Answer 1

$num_row=mysql_num_rows($sql);

应该

$num_row=mysql_num_rows($result);

Answer 2

Try this:

Count Rows after Query executes and get records.

$sql = "SELECT * FROM user WHERE username = '$uname' AND password = '$password'";
$result = mysql_query($sql);

$num_row=mysql_num_rows($result);
$row=mysql_fetch_array($result);

Answer 3

try this query

 $sql = "SELECT * FROM user WHERE username = '$uname' AND password = '$password'";
        $result=mysql_query($sql);

        $num_row=mysql_num_rows($result);

        $row=mysql_fetch_array($result);