SQL for sorting boolean column as true, null, false

Question

My table has three boolean fields: f1, f2, f3. If I do

SELECT * FROM table ORDER BY f1, f2, f3

the records will be sorted by these fields in the order false, true, null. I wish to order them with null in between true and false: the correct order should be true, null, false.

I am using PostgreSQL.

Answer 1

Not beautiful, but should work:

... order by (case when f1 then 1 when f1 is null then 2 else 3 end) asc