Database
[{"userId":"1","feedbackGiven":true},{"userId":"1","feedbackGiven":false},{"userId":"1","feedbackGiven":true},{"userId":"2","feedbackGiven":false},{"userId":"2","feedbackGiven":true}]
Query
db.collection.aggregate([{$group:{_id:"$userId",count:{$sum:1},feedBackFalseCount:{$sum:{$cond:[{$eq:["$feedbackGiven",false]},1,0]}}}}])