PHP mysqli query isnt working - php

Question

when the user enters their details they click on login but its not working, my connection to the database is fine its this file that is not working, any help would be appreciated, thanks
include '../connection.php'; //used to include connection file that is 1 level higher in the directory
$username = $_REQUEST['username'];
$password = $_REQUEST['password'];
$fquery = 'SELECT Username FROM login LIMIT 0, 30 ';
$squery = 'SELECT Password FROM login LIMIT 0, 30 ';
$username_query = mysqli_query($dbc, $fquery);
$password_query = mysqli_query($dbc, $squery);
$username_row = mysqli_fetch_array($username_query);
$password_row = mysqli_fetch_array($password_query);
if($username == $username_row && $password == $password_row) {
echo 'username and password correct';
}
?>

Answer 1

<?php
include '../connection.php'; //used to include connection file that is 1 level higher in the directory
$username = $_REQUEST['username'];
$password = $_REQUEST['password'];
$query = 'SELECT Username FROM login WHERE Username = ? AND Password = ?';
/* set a default value to check against */
$valid_user = '';
/* use prepared statement */
$stmt = mysqli_stmt_init($dbc);
if (mysqli_stmt_prepare($stmt, $query)) {
/* set question marks equal to values */
mysqli_stmt_bind_param($stmt, 'ss', $username, $password);
mysqli_stmt_execute($stmt);
/* get the valid username only if query is successful */
mysqli_stmt_bind_result($stmt, $valid_user);
mysqli_stmt_fetch($stmt);
/* close the statment */
mysqli_stmt_close($stmt);
}
/* check if default was overwritten */
if($valid_user != '') {
echo 'username and password correct';
}
?>
Try this out, should accomplish what you are trying to do.

Answer 2

$username_query = mysqli_query($dbc, $fquery);
$password_query = mysqli_query($dbc, $squery);
$username_row = $username_query->fetch_array(MYSQLI_ASSOC);
$password_row = $password_query->fetch_array(MYSQLI_ASSOC);
if($username == $username_row['username'] && $password == $password_row['Password']) {
echo 'username and password correct';
}

Answer 3

$username = mysqli_real_escape_string($dbc, $_REQUEST['username']);
$password = mysqli_real_escape_string($dbc, $_REQUEST['password']);
$query = "SELECT * FROM login WHERE Username = '$username' AND Password = '$password' LIMIT 1";
if(mysqli_num_rows($query) > 0)
echo 'username and password correct';