Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{users:"someuser@gmail.com"},{users:["someuser@gmail.com"]}]
Query
db.collection.aggregate([{$addFields:{users:{$cond:[{$eq:[{$type:"$users"},"string"]},["$users"],"$users"]}}}])
Result