Lookback API: queries for empty date fields

Question

We have a date field in our test cases called "Retire Date" that allows us to retire test cases without deleting them.

I'd like to know how many testcases are not retired on a particular date. How do I refer do a date field that has no entry in it? Do I use null, empty string or something else? I've tried for example:

_Type: 'TestCase',
__At: '2012-11-01',
c_RetireDate: {$ne: null}

But this does not seem to work, nor an empty string. I'm also interested in the opposite case, but the following does not seem to work to get all cases where a retire date is not set:

_Type: 'TestCase',
__At: '2012-11-01',
c_RetireDate: null

How do I make these queries for empty custom date fields?

Answer 1

Ok, sorry, the above actually works fine-- it was a bug in my program.