How can I fix this MySQL Code - php

Question

How can I fix the following code?
function userExists($pdow, $login)
{
$userQuery = "SELECT * FROM login u WHERE login=:user;";
$stmt = $pdow->prepare($userQuery);
$stmt->execute(array(':user' => $login));
return !!$stmt->fetch(PDO::FETCH_ASSOC);
}
$login = 'user';
$exists = userExists($pdow, $login);
if('$login')
$user= var_dump((bool) 'Exists');
{
echo "Login exsists!";
}
I have two problems with my code.
First error:
Error with echoing 'login exsists!'. I see this echo all the time in browser.
Second error:
When I get echo 'login exsists!' my code still inserts data to database.

Answer 1

Simply:
$servername = '';
$dbname = '';
$username = '';
$password = '';
$dbh = new PDO("mysql:host={$servername};dbname={$dbname}", $username, $password);
function user_exists($dbh, $Login) {
$Q = $dbh->prepare("SELECT * FROM login WHERE login = :Login");
$Q->bindParam(':Login', $Login);
$Q->execute();
return $Q->fetch(PDO::FETCH_ASSOC);
}
//Lets try:
$user = user_exists($dbh, 'email#example.com');
if ($user) {
echo 'User: ' . $user['login'] . ' was found in the database.';
} else {
echo 'The user was NOT found.';
}

Answer 2

if($login)
// this line doesnt make any sense!
// $user= var_dump((bool) 'Exists');
// so this is not a valid if clause
{
echo "Login exsists!";
}`

Answer 3

try {
$pdow = new PDO('mysql:host=localhost;dbname=log_cdr', 'root', 'slawek132');
$pdow -> query ('SET NAMES utf8');
$pdow -> query ('SET CHARACTER_SET utf8_unicode_ci');
$pdow->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sqlw = "INSERT INTO login (login, pass, pass_v, email, email_v)
VALUES ('".$_POST["login"]."','".$_POST["pass"]."','".$_POST["pass_v"]."','".$_POST["email"]."','".$_POST["email_v"]."')";
function user_exists($login) {
$Q = pdow()->prepare("SELECT * FROM login WHERE login = :Login");
$Q->bindParam(':login', $Login);
$Q->execute();
if ($Q->rowCount() != 0) {
//User exist:
return $Q->fetch(PDO::FETCH_ASSOC);
} else {
//User doesn't exist.
return false;
}
}