query question

I have a table:

michael=# \d healthnotes
                                    Table "public.healthnotes"
  Column |           Type           |                          Modifiers
--------+--------------------------
+-------------------------------------------------------------
  posted | timestamp with time zone | not null default
('now'::text)::timestamp(6) with time zone
  notes  | text                     |
Indexes: healthnotes_pkey primary key btree (posted)

Often there are multiple entries per day. I want to display the day
once, with all the entries on that day.

So do I select * from notes and group by date, then write a nested
for-loop in php that ignores the extra timestamp items? Seems a little
inelegant. Or can I select distinct timestamps somehow after converting
them to dates?

Not sure how to go about this.