Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{unionid:7,openapi:2},{unionid:7,},{unionid:17,openapi:4},{unionid:74,openapi:5}]
Query
db.collection.update({},[{$set:{openapi:"$unionid"}}],{multi:true})
Result