Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{"field1":10,"field2":25},{"field1":5,"field2":44},{"field1":55,"field2":1},]
Query
db.collection.find({$expr:{$gt:[{$abs:{$subtract:["$field1","$field2"]}},20]}},)
Result