How to sort NULL values last using Eloquent in Laravel

Question

I've got a many-to-many relationship between my employees and the group table. I've created the pivot table, and all is working correctly with that. However, I've got a sortOrder column on my employees' table that I use to determine the order in which they display. An employee with a value of 1 in the sortOrder column should be first, a value of 2 should be second, and so on. (Or backward if sorted descending) The sortOrder column is an integer column that allows null values.

I've set up my group model to sort the employees by the sort column, but I've run into a problem. The null values always are displayed first. I've tried using ISNULL and similar SQL methods in place of the regular "asc" or "desc" used, but I only get an error.

Here's the code in my Group model:

class Group extends Eloquent {

public function employees()
    {
        return $this->belongsToMany("Employee")->orderBy('sortOrder', 'asc');
    }
}

And here's what I use in the controller to access my model:

$board = Group::find(6)->employees;

What's the trick in Laravel to sorting NULL values last?

Answer 1

Laravel does not take into consideration the ISNULL method however, you can pass it in as a raw query and still make use of it as it's more efficient than IF statements and the results will stay the same if you ever go beyond 1000000 employees (accepted answer), like so:

public function employees()
{
    return $this->hasMany('Employee')
                ->orderBy(DB::raw('ISNULL(sortOrder), sortOrder'), 'ASC');
}

Update: You can also use the orderByRaw() method:

public function employees()
{
    return $this->hasMany('Employee')
                ->orderByRaw('ISNULL(sortOrder), sortOrder ASC');
}