MongoDB distinct aggregation

Question

I\'m working on a query to find cities with most zips for each state:

db.zips.distinct(\"state\", db.zips.aggregate([ {$group:{_id:{state:\"$state\", city:\"         


        

Answer 1

You can call $setUnion on a single array, which also filters dupes:

{ $project: {Package: 1, deps: {'$setUnion': '$deps.Package'}}}