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db.collection.aggregate([{"$set":{"A_set":{"$filter":{"input":"$A_set","as":"x","cond":{"$ne":["$$x",{}]}}}}},{"$set":{"A_count_set":{"$filter":{"input":"$A_count_set","as":"x","cond":{"$ne":["$$x",{}]}}}}},{"$set":{"B_set":{"$filter":{"input":"$B_set","as":"x","cond":{"$ne":["$$x",{}]}}}}},{"$set":{"B_count_set":{"$filter":{"input":"$B_count_set","as":"x","cond":{"$ne":["$$x",{}]}}}}}])