MySQLi Num行不起作用

Question

i have a simple login system and i get nothing when trying to fetch the number of rows, the same method used to work all the time, i dont know what is going on today.

Code:

<?php
class LoginClass {
    public $User;
    public $Pass;
    public $Query;
    function Init() {
        $User = $this->User;
        $Pass = $this->Pass;
        if($User != '')
        {
            if($Pass != '')
            {
                $this->HashPass();
            }
            else
            {
                echo 'Please Enter A Password.';
            }
        }
        else
        {
            echo 'Please Enter A Username or E-Mail.';
        }
    }

    function HashPass() {
        $Pass = $this->Pass;
        $this->Pass = hash('sha256', $Pass);
        $this->CheckUser();
    }

    function CheckUser() {
        $User = $this->User;
        if(!filter_var($User, FILTER_VALIDATE_EMAIL))
        {
            $this->Query = 'SELECT * FROM Users WHERE User = "'.$User.'" AND Pass = "'.$this->Pass.'"';
        }
        else
        {
            $this->Query = 'SELECT * FROM Users WHERE EMail = "'.$User.'" AND Pass = "'.$this->Pass.'"';
        }
        $this->CheckDB();
    }

    function CheckDB() {
        $Query = $this->Query;
        $Connect = new mysqli("127.0.0.1", "root", "", "Data");
        $Stmt = $Connect->prepare($Query)
        $Stmt->execute();
        $Stmt->store_result();
        echo $Stmt->num_rows;
        $Stmt->close();
        $Connect->close();
    }

    function SetupSession() {
        echo 'Test';
    }
}

the Check DB is the problem here and im able to echo out the query variable in that function everything is fine, here is exactly what i get

SELECT * FROM Users WHERE User = "Test" AND Pass = "532eaabd9574880dbf76b9b8cc00832c20a6ec113d682299550d7a6e0f345e25"

I also checked my DB and all my tables are setup correctly and there is no password.

Answer 1

OK, need more space than the comments area, the issue is clearly in this block:

function CheckDB() {
    $Query = $this->Query;
    $Connect = new mysqli("127.0.0.1", "root", "", "Data");
    $Stmt = $Connect->prepare($Query)
    $Stmt->execute();
    $Stmt->store_result();
    echo $Stmt->num_rows;
    $Stmt->close();
    $Connect->close();
}

I think it's because you aren't binding parameters to the prepared statement, you've already included them inline in your earlier statement. Therefore, you probably want to:

Switch to non-prepared statement

The easy option here will be to switch to a non-prepared statement. Replace your block with:

function CheckDB() {
    $Query = $this->Query;
    $Connect = new mysqli("127.0.0.1", "root", "", "Data");
    $Stmt = $Connect->query($Query)
    echo $Stmt->num_rows;
    $Stmt->close();
    $Connect->close();
}

A word of caution with this approach: you need to sanitize your user input in the block which defines $User , otherwise you're leaving yourself open to mysql injection. In that block, change this line:

$User = $this->User;

To the following:

$User = mysql_real_escape_string($this->User);