List results by scope where (field) not nil THEN second condition

Question

I'm wondering if there's a way to make one query to get the following conditions:

1) scope :scheduled_for, -> {where.not(:scheduled_for => nil)}

then

2) scope :sort_by_position, -> {order('position')}

The expected result would be the following list:

• Post 1 (Sept 23 && Position 1)
• Post 2 (Sept 24 && Position 2)
• Post 3 (Position: 3)
• Post 4 (Position: 4)
• etc...

Note: the position field could be random (i.e. Post 1 could have a position of 5 but since its scheduled_for is not empty, it takes precedence over a lower position post.

Answer 1

You can specify multiple conditions in the order_by

order_by('scheduled_for IS NULL, position')

scheduled_for IS NULL returns "1" if true, "0" is false, so NULL values are greater (i.e. show up at the end of the list)