Method: Mongo::Collection#distinct

Defined in:
lib/mongo/collection.rb

#distinct(field_name, filter = nil, options = {}) ⇒ Array<Object>

Get a list of distinct values for a specific field.

Examples:

Get the distinct values.

collection.distinct('name')

Parameters:

  • field_name (Symbol, String) —

    The name of the field.

  • filter (Hash) (defaults to: nil) —

    The documents from which to retrieve the distinct values.

  • options (Hash) (defaults to: {}) —

    The distinct command options.

Options Hash (options):

  • :max_time_ms (Integer) —

    The maximum amount of time to allow the query to run, in milliseconds. This option is deprecated, use :timeout_ms instead.

  • :read (Hash) —

    The read preference options.

  • :collation (Hash) —

    The collation to use.

  • :session (Session) —

    The session to use.

  • :timeout_ms (Integer) —

    The operation timeout in milliseconds. Must be a non-negative integer. An explicit value of 0 means infinite. The default value is unset which means the value is inherited from the collection or the database or the client.

Returns:

  • (Array<Object>) —

    The list of distinct values.

Since:

  • 2.1.0



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# File 'lib/mongo/collection.rb', line 771

def distinct(field_name, filter = nil, options = {})
  View.new(self, filter || {}, options).distinct(field_name, options)
end