Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{name:"doc1",moniker:"doc1",arr:[1,2],},{name:"doc2",arr:[3,3],}]
Query
db.collection.find({"$expr":{"$eq":[{"$arrayElemAt":["$arr",0]},{"$arrayElemAt":["$arr",1]}]}})
Result