i've been using a database determining the posts with the aid of the BaseColumns interface. its pretty standard implementation. however i am interested in the Count constant pointed out there. i'm utilizing a content provider for that queries so a custom count query is not really a choice. to date i've been while using query count having a projection of just the ids, appeared more lighweight this way.

what's the _COUNT area in BaseColumns employed for? i'm presuming its for any count of rows. how do you build the plan with this area?
how do you query the count?