Query for documents where array size is greater than 1

Question

I have a MongoDB collection with documents in the following format:

{
  \"_id\" : ObjectId(\"4e8ae86d08101908e1000001\"),
  \"name\" : [\"Name\"],
  \"zipcod         


        

Answer 1

I believe this is the fastest query that answers your question, because it doesn't use an interpreted $where clause:

{$nor: [
    {name: {$exists: false}},
    {name: {$size: 0}},
    {name: {$size: 1}}
]}

It means "all documents except those without a name (either non existant or empty array) or with just one name."

Test:

> db.test.save({})
> db.test.save({name: []})
> db.test.save({name: ['George']})
> db.test.save({name: ['George', 'Raymond']})
> db.test.save({name: ['George', 'Raymond', 'Richard']})
> db.test.save({name: ['George', 'Raymond', 'Richard', 'Martin']})
> db.test.find({$nor: [{name: {$exists: false}}, {name: {$size: 0}}, {name: {$size: 1}}]})
{ "_id" : ObjectId("511907e3fb13145a3d2e225b"), "name" : [ "George", "Raymond" ] }
{ "_id" : ObjectId("511907e3fb13145a3d2e225c"), "name" : [ "George", "Raymond", "Richard" ] }
{ "_id" : ObjectId("511907e3fb13145a3d2e225d"), "name" : [ "George", "Raymond", "Richard", "Martin" ] }
>