What's wrong with this Solr range filter query?

Question

The following filter query returns zero results (using *:* as query):

-startDate:[* TO *] OR startDate:[* TO NOW/DAY+1DAY]

But if I filter

Answer 1

I used femtoRgon's answer and was able to construct a query that included a range and blank values.

The following includes all docs with a StartDate on or after 1/1/2014 and all docs without a StartDate.

(StartDate:[2014-01-01T00:00:00Z TO *]) OR (-StartDate:([* TO *]) AND *:*)

The magic is (-StartDate:([* TO *]) AND *:*). This will select the docs without a StartDate.