I have seen this, this and a couple of other examples. Some have no solutions and the rest have workarounds.
My question is: As of today (May 2019), is there a way of updating a mongodb field with the value of another field. For example:
//Document example:
{
_id : '1aa',
fieldA : 0,
fieldB : 30,
}
//update command
db.exampleDocument.update(
{ _id: { $in: ['1aa', '2bb', '3cc'] } },
{ $set: { fieldA : $[elem].fieldB } }
)
Where for each document I will get the value of that document's fieldA replaced by the value of that document's fieldB. Is this possible with mongoDB or mongoose, without any looping?
