ruby - How do I get MIN in Postgres to play nice with Rails? -

ruby - How do I get MIN in Postgres to play nice with Rails? -

right now, have enormous query i'm running in rails:

@foo_collection = foo.select(' foos.id, array_agg() some_aggregate, -- 20 of these, they're not problem min(bars.some_date), -- returning wrong type - problem ').joins(' inner bring together bars... -- lot of joins - not problem ').where(' some_conditions ').group(' foos.id ')

this query pulls info want according pgadmin. doesn't translate rails. trying process @foo_collection.some_date datetime object create time difference results in this:

undefined method `-' "2014-04-01 16:12:35.461712":string

is there way coax pg output give rails datetime instead of string, or have tell rails parse some_dates strings?

so far, i've handled having rails convert @foo_collection.some_dates to_datetime, to_f can find time lapses between them. has important overhead - it'd much easier if withdraw datetime object straight db.

rails pulling field string because you're not querying model defined column type, think best bet might alter query output table , utilize rails model query table.

ruby-on-rails ruby ruby-on-rails-3 postgresql