finding where by using IN operator in rails3

Question

I am trying to run a sql like below

select name from appointments where location_id in (2,3,4)

the following does not work. I am using PostgreSQL

a = [2,3,4]
Appointment.select(:name).where("location_id IN ?", a)

ActiveRecord::StatementInvalid: PGError: ERROR:  syntax error at or near "2"
LINE 1: ... FROM       "appointments"  WHERE     (location_id IN 2,3,4)
                                                                 ^
: SELECT     name FROM       "appointments"  WHERE     (location_id IN 2,3,4)

Answer 1

You can use this:

Appointment.select(:name).where(:location_id => [2,3,4])

Hope this helps

Answer 2

I don't know rails, but it looks to me like you need to do this:

Appointment.select(:name).where("location_id IN (?)", a)

i.e., put brackets around the ?.