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

There's a more efficient way to do this in MongoDB 2.2+ now that you can use numeric array indexes in query object keys.

// Find all docs that have at least two name array elements.
db.accommodations.find({'name.1': {$exists: true}})

You can support this query with an index that uses a partial filter expression (requires 3.2+):

// index for at least two name array elements
db.accommodations.createIndex(
    {'name.1': 1},
    {partialFilterExpression: {'name.1': {$exists: true}}}
);