Ruby-on-Rails: Selecting distinct values from the model

The docs: http://guides.rubyonrails.org/active_record_querying.html#selecting-specific-fields

Clearly state that:

query = Client.select(:name).distinct
# => Returns unique names

However, when I try that in my controller, I get the following error:

undefined method `distinct' for #<ActiveRecord::Relation:0xb2f6f2cc>

To be clear, I want the distinct names, like ['George', 'Brandon'], not the clients actual records. Is there something that I am missing?