User Registration form - PHP

<?php
include($_SERVER['DOCUMENT_ROOT'] . '/db.php');
?>

<!DOCTYPE html>
<html>
<head>
	<title>Login or SignUp</title>
</head>
<body>
	<h2>Signup</h2>

	<form action="" method="POST">
		Email:
		<input type="text" name="email"><br>
		Username:
		<input type="text" name="username"><br>
		Name:
		<input type="text" name="name"><br>
		Password:
		<input type="password" name="password"><br>
		Confirm Password:
		<input type="password" name="confirm_password"><br>
		<input type="submit" name="user_register" value="Register">
	</form>

<?php
if(isset($_POST['user_register'])){

	// Validate username
	if(empty(trim($_POST['username']))){
		$username_err = "Please Enter a Username.";
	} else {
		$sql = "SELECT user_id FROM user WHERE username = :username";

		if($statement = $connect->prepare($sql)){
			$statement->bindParam(':username', $username);
			$param_username = trim($_POST['username']);
			if($statement->execute()){
				if($statement->rowCount() == 1){
					$username_err = "This username is already taken.";
				} else {
					$username = trim($_POST['username']);
				}
			}
		unset($statement);
		}
	}

	// Validate Password
	if(empty(trim($_POST['password']))){
		$password_err = "Please enter a password.";
	} elseif(strlen(trim($_POST['password'])) < 6) {
		$password_err = "Password must have atleast 6 characters.";
	} else {
		$password = trim($_POST['password']);
	}

	// Validate confirm Password
	if(empty(trim($_POST['confirm_password']))){
		$confirm_password_err = 'Please confirm password.';
	} else {
		$confirm_password = trim($_POST['confirm_password']);
		if($password != $confirm_password){
			$confirm_password_err = "Password did not match.";
		}
	}

	// Validate email
	if(empty($_POST['email'])){
		$email_err = "Email is Required.";
	} else {
		$email = $_POST['email'];
		if(!filter_var($email, FILTER_VALIDATE_EMAIL)){
			$email_err = "Invalid email format.";
		}
		else {
			$email = filter_var($email, FILTER_VALIDATE_EMAIL);
		}
	}

	// Check input errors before inserting in database
	if(empty($username_err) && empty($password_err) && empty($confirm_password_err) && empty($email_err)){
		$sql = "INSERT INTO user (username, user_name, user_password, user_email) VALUES (:username, :user_name, :password, :email)";
		if($statement = $connect->prepare($sql)){
			$statement->bindParam(':username', $param_username);
			$statement->bindParam(':password', $param_password);
			$statement->bindParam(':user_name', $param_user_name);
			$statement->bindParam(':email', $param_user_email);
			$param_username = $username;
			$param_password = password_hash($password, PASSWORD_DEFAULT);
			$param_user_email = $email;
			$param_user_name = $_POST['name'];
			if($statement->execute()){
				header("location: login.php");
			} else {
				echo "Something went wrong. Please try again later.";
			}
		}
		unset($statement);
	}
	unset($connect);

}

?>

</body>
</html>