select and group in rails 1.2

that's because :select expects a string, not an array. the array is
getting converted to a string and that is the result

irb(main):001:0> [:tracker, :job_id].to_s
=> "trackerjob_id"

so you want

:select => "tracker, job_id"

also, your condition is a bit strange.

is job_id an integer column? why are you using = and %? you want
every record where job_id begins with 3?

if you are passing in [:x, :y] and getting back "xy" then that means
the array is being converted to a string. pass it a string.

from the api

:select: By default, this is * as in SELECT * FROM, but can be changed
if you for example want to do a join, but not include the joined
columns.

from the source

        def construct_finder_sql(options)
          scope = scope(:find)
          sql = "SELECT #{(scope && scope[:select]) ||
options[:select] || '*'} "

so as you can see, options[:select] in the above

"#{[:a, :b]}" => "ab"