Database
[{"_id":{"aC":"BE","aI":"HBEU","aN":"12345","aT":"CA"},"bal":{"type":"E","date":"2015-08-02"}},{"_id":{"aC":"BE","aI":"HBEU","aN":"67890","aT":"CA"},"bal":{"type":"E","date":"2015-08-01"}}]
Query
db.collection.aggregate([{$sort:{"bal.date":-1}}])