Update a field in mysql - php

Question

I have this code here:
$userid = Secure($_POST[ 'username' ]);
$user = $db->where('username', $userid)->getOne('users',array('id','web_device_id','is_pro'));
$is_user_matches = $db->where('user_id', $user['id'])->where('like_userid', self::ActiveUser()->id)->getOne('likes', array('id'));
$id = $db->where('user_id', self::ActiveUser()->id)->where('like_userid', $user['id'])->getValue('likes', 'id');
$saved = false;
if ($id > 0) {
$saved = $db->where('id', $id)->update('likes', array(
'user_id' => self::ActiveUser()->id,
'like_userid' => $user['id'],
'is_like' => 1,
'is_dislike' => 0,
'created_at' => date('Y-m-d H:i:s')
));
} else {
if(isUserLiked($user['id']) === false) {
$saved = $db->insert('likes', array(
'user_id' => self::ActiveUser()->id,
'like_userid' => $user['id'],
'is_like' => 1,
'is_dislike' => 0,
'created_at' => date('Y-m-d H:i:s')
));
}
}
These are the actions that occur when a user presses the LIKE button!
Now, my question is. How can I add in addition to these codes, an UPDATE for a table in mysql?
I would like that when a user gives a Like to a person, he will count automatically.
mysql_query("
UPDATE users
SET likes = likes + 1
WHERE id = '".$user['id']."'
");
I tried to add this code but I couldn't. I don't think I'm adding it where it should be. Can you show me an example please?