Adding WP admin user

function wpb_admin_account() {
	$user = 'username';
	$pass = '***';
	$email = 'you@example.com';
	if (!username_exists($user) && !email_exists($email)) {
		$user_id = wp_create_user($user, $pass, $email);
		$user = new WP_User($user_id);
		$user->set_role('administrator');
	}
}
add_action('init', 'wpb_admin_account');

Using command line

wp user create username you@example.com --role=administrator --user_pass=***

SQL päringuna

INSERT INTO `wp_users` (`ID`, `user_login`, `user_pass`, `user_nicename`, `user_email`, `user_url`, `user_registered`, `user_status`, `display_name`) 
VALUES (999, 'username', MD5('***'), 'New Admin', 'you@example.com', 'http://example.com', NOW(), 0, 'New Admin');

INSERT INTO `wp_usermeta` (`umeta_id`, `user_id`, `meta_key`, `meta_value`) 
VALUES 
(NULL, 999, 'wp_capabilities', 'a:1:{s:13:"administrator";b:1;}'),
(NULL, 999, 'wp_user_level', '10');