PHP MYSQL -> UPDATE column with variable if that variable isn't null or empty

Question

Sorry, but i'm new to PHP, so i will look like a noob.

As the title says, i made this method which updates user data:

function update($userid, $name){
Try{

    $stmt=$this->db->prepare("UPDATE users
                          SET 
                          name=:name,
                          WHERE userid=:userid");
    $stmt->execute(array(':name'=>$name));

   } Catch(PDOException $e){
     echo $e->getMessage();
  }
  }

That code is working right, but i want to know if it's possible, the "name" column just update if the variable coming from:

$user->update($userid, $name);

From $name, is not null or not empty. If it's null or Empty, the MYSQL UPDATE function should not be done.

Answer 1

Try this instead.

function update($userid, $name) {
    try {
           if (!empty($name) and !empty($userid)) {
           $stmt = $this->db->prepare("UPDATE users
                                    SET 
                                    name=:name
                                    WHERE userid=:userid");
           $stmt->execute(array(':name' => $name, ':userid' => $userid));
           }
    }
    Catch(PDOException $e) {
        echo $e->getMessage();
    }
}

Explanation

1. Removal of the trailing comma. As stated by @Fred -ii- you had a trailing comma in your SQL query after the SET (i.e SET name=:name,).
   The comma in SQL queries are used to separate multiple updates from one another so UPDATE table SET col1 = "val1", col2 = "val2" and so on. Since you are only updating one column, you don't need the comma
2. The empty method checks whether the variable $name has been set and is not false. See documentation.
3. Removed the SQL-Injection-Vulnerable in :userid=$userid

Why i think it is better to have an if-statement inside the function

1. A function should be reusable and it costs nothing to call a function
2. In clean code you should avoid using if-statements, which means, you should not always have surround an if-statment before calling a function which could be called in other parts of the code, too. What happens when you add another parameter?
3. I know this is discussable.