php errors（警告：mysql_fetch_array（）：提供的参数不是有效的MySQL结果资源

Question

$sorgu=mysql_query("SELECT * FROM  users WHERE UserName='$userName' AND  Password='$password'"); 
if( mysql_affected_rows() )
{
    **$row=mysql_fetch_array($sorgu);**            /// this line is erorr
    if(in_array($row["UserID"],$_SESSION["id_array"]))
    {
        echo "session is already open";
    }


    else
    {

        $array=array(
            "id" => $row["UserID"],
            "userName" => $row["UserName"],
            "email" => $row["Email"],
            "admin" => $row["admin"],
        );


        $_SESSION["login"]=true;

        $_SESSION["array"][$row["UserID"]] = $array;

        $_SESSION["id_array"][]=$row["UserID"];

        $_SESSION["userid"] = $row["UserID"];

        header("Location: index.php");

Answer 1

使用＆＃34; mysql_num_rows（$ sorgu）＆gt; 0＆＃34;而不是第2行的mysql_affected_rows（）

mysql_affected_rows（）用于检查UPDATE和INSERT，而不是SELECT。