Database
[{_id:">Books>IT>C#>Cloud computing>"}]
Query
db.collection.aggregate([{$project:{"Split":{"$filter":{"input":{"$split":["$_id",">"]},"as":"categories","cond":{"$ne":["$$categories",""]}}},_id:0}},{$project:{_id:{$last:"$Split"},"Path":{"$reduce":{"input":{$slice:["$Split",0,{$subtract:[{$size:"$Split"},1]}]},"initialValue":">","in":{"$concat":["$$value","$$this",">"]}}}}}])