[{"_id":"5a2ca2227c42ad67682731d4",/** this is user id*/"name":"Hemadri Dasari",createdAt:"2021-04-08T04:05:30.340Z",updatedAt:"2021-04-08T04:05:30.340Z","departments":[{"_id":"5a2ca2227c42ad6768271232","name":"Digital","userId":"5a2ca2227c42ad67682731d4",createdAt:"2021-04-08T04:05:30.340Z",updatedAt:"2021-04-08T04:05:30.340Z","projects":[{"_id":"5a2ca2227c42ad6768274343","name":"Digital","departmentId":"5a2ca2227c42ad6768271232",createdAt:"2021-04-09T04:05:30.340Z",updatedAt:"2021-04-09T04:05:30.340Z",},{"_id":"5a2ca2227c42ad6768274344","name":"Digital","departmentId":"5a2ca2227c42ad6768271232",createdAt:"2021-04-08T04:05:30.340Z",updatedAt:"2021-04-08T04:05:30.340Z",},{"_id":"5a2ca2227c42ad6768274345","name":"Digital","departmentId":"5a2ca2227c42ad6768271232",createdAt:"2021-04-08T04:05:30.340Z",updatedAt:"2021-04-08T04:05:30.340Z",}]},{"_id":"5a2ca2227c42ad6768271233","name":"Finance","userId":"5a2ca2227c42ad67682731d4",createdAt:"2021-04-08T04:05:30.340Z",updatedAt:"2021-04-08T04:05:30.340Z","projects":[{"_id":"5a2ca2227c42ad6768274346","name":"Digital","departmentId":"5a2ca2227c42ad6768271233",createdAt:"2021-04-08T04:05:30.340Z",updatedAt:"2021-04-08T04:05:30.340Z",},{"_id":"5a2ca2227c42ad6768274347","name":"Digital","departmentId":"5a2ca2227c42ad6768271233",createdAt:"2021-04-08T04:05:30.340Z",updatedAt:"2021-04-08T04:05:30.340Z",},{"_id":"5a2ca2227c42ad6768274348","name":"x","departmentId":"5a2ca2227c42ad6768271233",createdAt:"2021-04-08T04:05:30.340Z",updatedAt:"2021-04-08T04:05:30.340Z",}]}]}]

db.collection.aggregate([{$match:{_id:"5a2ca2227c42ad67682731d4"}},{$unwind:"$departments"},{$unwind:"$departments.projects"},{$match:{"departments.projects.createdAt":{$gte:"2021-04-09T00:00:00Z"}}}])