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db.collection.aggregate([{$group:{_id:"$user",task1:{$push:"$task1"},task2:{$push:"$task2"},task3:{$push:"$task3"}}},{$project:{_id:0,userId:"$_id",tasks:{"$concatArrays":["$task1","$task2","$task3"]}}},{$project:{userId:1,"Spirituality":{$sum:"$tasks.Spirituality"},"Humor":{$sum:"$tasks.Humor"},"Fairness":{$sum:"$tasks.Fairness"}}}])