:select with find_in_batches

How can I include a :select clause with find_in_batches. The following
throws an error " Mysql::Error: Unknown column 'users.id' in 'field
list': .

    Post.find_in_batches(:batch_size => 100, :select => "users.id,
users.name, categories.name, posts.id", :include =>
[:user, :category]) do |group|
    #stuff with group
    end

How can I include a :select clause with find_in_batches. The following
throws an error " Mysql::Error: Unknown column 'users.id' in 'field
list': .

If you want joins use :joins rather than :include

Fred