> Is it possible to have date type data that only contain month and year?,
> how can I obtain that from a timestamp (without time zone) column?
I think you want date_trunc, which will cut everything down to the first
of the month, e.g 2015-01-01, 2015-02-01, etc. The results will still be
dates, so you can still use date functions to manipulate them.
Paul