[{"title":"a","active":true},{"title":"a","active":false},{"title":"a","active":false},{"title":"b","active":true},{"title":"b","active":false},{"title":"c","active":true}]

db.collection.aggregate([{"$group":{"_id":"$title","total":{"$sum":1},"active":{"$sum":{"$toInt":"$active"}}}}])