Finding distinct unique IDs in documents returned by fq -- Urgent Help Req

[Ninad Raut]

Hi,

I have a scenario in which I have to find count of distinct unique IDs
present in a field (rootId field in my case) for a particular query.

I require this for pagination purpose.

Is there a way in Solr to do something like this we do in SQL:

select count(distinct(rootId))
from table
where (the query part).


Regards,
Ninad R