Database
[{"resolved_at":"2020-05-23 05:57:40","botExecResult":"BotSuccess"},{"resolved_at":ISODate("2020-05-23T05:23:00Z"),"botExecResult":"BotSuccess"}]
Query
db.collection.aggregate([{"$match":{"botExecResult":"BotSuccess","$and":[{"resolved_at":{"$type":"string","$ne":""}}]}},{$project:{date:{$dateToString:{date:{$toDate:"$resolved_at"},format:"%Y-%m-%d"}}}}])