Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{"name":"My name","pictures":["Pic1","Pic2","Pic3","Pic4","Pic5"],}]
Query
db.collection.aggregate([{$project:{name:1,pictires:{$arrayElemAt:["$pictures",{$mod:[{$toLong:"$$NOW"},{$size:"$pictures"}]}]}}}])
Result