[{"hotelcode":"a","availdates":["2020-01-02","2020-02-03"]},{"hotelcode":"a","availdates":["2020-02-03"]},{"hotelcode":"b","availdates":[]},{"hotelcode":"b","availdates":["2020-01-02"]},{"hotelcode":"c","availdates":["2020-01-02","2020-02-03"]},]

db.collection.aggregate({$match:{"availdates":{"$gt":"1"}}},{$group:{_id:"$hotelcode","records":{$push:"$$ROOT"},"dataCount":{$sum:1}}})