SQL for sorting boolean column as true, null, false
Not beautiful, but should work:
... order by (case when f1 then 1 when f1 is null then 2 else 3 end) asc
A better solution would be to use
f1 DESC NULLS LAST
if you're okay with the order true, false, nil ( I guess the important part of your question was, like in my situation now, to have the not-true vaules together)
you could do also as follows:
order by coalesce(f1, FALSE), coalesce(f1, TRUE), ...If f1 is TRUE, you get: TRUE, TRUE
If f1 is NULL, you get: FALSE, TRUE
If f1 is FALSE, you get: FALSE, FALSE
which corresponds to the sorting order you want.