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

[T-SQL]:

select [case], count(*) tally
from (
  select 
  case when [processed_timestamp] is null then 'null'
  else 'not null'
  end [case]
  from myTable
) a 

And you can add into the case statement whatever other values you'd like to form a partition, e.g. today, yesterday, between noon and 2pm, after 6pm on a Thursday.