Question

Undefined method errors when I try to use a column alias for an aggregate (PostgreSQL)

Inside my model:

class B2bLoginAttempt < ActiveRecord::Base
  set_table_name "b2b_logins"
end

Inside my controller:

    @client_ip = request.env['REMOTE_ADDR']
    @sql = "select count(id) as failed_logins FROM b2b_logins WHERE ip_address = '"+@client_ip+"'"

    f = B2bLoginAttempt.find_by_sql(@sql)
    failed_attempts = f.failed_logins.to_s
    f.destroy

Then I see: undefined method `failed_logins’ for #<Array:0x104d08478>

Answer 1

The error occurs because find_by_sql returns an array, so you need to write f.first.failed_logins.to_s instead of f.failed_logins.to_s.
Check find_by_sql doc here.