[{"_id":0,"courseId":"NIE-AIB","moduleId":"CYB-001","module_name":"CYBSEC","item_code":"FOO-001"},{"_id":1,"courseId":"NIE-EUC","moduleId":"MTH-001",/** "module_name": "MTHINT",*/"item_code":"BAR-001"},{"_id":2,"courseId":"NIE-IOD","moduleId":"WRT-001","module_name":"WRTINT",/** "item_code": "BAZ-001"*/},{"_id":3,"courseId":"NIE-YAD",/** "moduleId": "HST-001",* "module_name": "HSTEUR",* "item_code": "QAZ-001"*/},]

db.collection.aggregate([{"$project":{"_id":0,"courseId":{"$ifNull":["$courseId",null]},"moduleId":{"$ifNull":["$moduleId",null]},"module_name":{"$ifNull":["$module_name",null]},"item_code":{"$ifNull":["$item_code",null]}}}])