How do I return my records grouped by NULL and NOT NULL?

Question

I have a table that has a processed_timestamp column -- if a record has been processed then that field contains the datetime it was processed, otherwise it is null.

Answer 1

If it's oracle then you can do:

select decode(field,NULL,'NULL','NOT NULL'), count(*)
from table
group by decode(field,NULL,'NULL','NOT NULL');

I'm sure that other DBs allow for similar trick.