How to get a list of users in a certain role?

Question

I'm creating a module in Drupal 7 that needs to get a list of users from a certain role. I've seen examples showing how to get the logged in user's role, and a list of roles, but I haven't seen anything to help me get the list of users in a certain role. Is there a way to do this? I was trying to use user_role, but that only gave me a list of the roles that existed. Is there something else I should be doing with it?

Answer 1

user_roles() is actually implemented in such a way that it searches the roles database table to extract all roles. You could do similar thing and search the users table for a given role. Please look at the function below

function getUsersByRole($rid = 1) { // rid = Role Id from users_roles table
    $query = db_select('users', 'u');
    $query->fields('u', array('uid', 'name'));
    $query->innerJoin('users_roles', 'r', 'r.uid = u.uid');
    $query->condition('r.rid', $rid);
    $query->orderBy('u.name');

    $result = $query->execute();

    $users = array();
    foreach ($result as $user) {
        $users[] = $user;
    }

    return $users;
}

$users = getUsersByRole(3);
var_dump($users);

Make sure you will run it within Drupal environment.