On Mon, Oct 10, 2011 at 5:17 PM, Rich Shepard <rshepard@xxxxxxxxxxxxxxx> wrote: > I'm trying to query the table to extract the single highest value of a > chemical by location and date. This statement gives me all the values per > stream, site, and date: > > SELECT str_name, site_id, sample_date, max(quant) FROM chemistry WHERE hydro > = 'Humboldt' group by str_name, sample_date, site_id order by str_name, > site_id; > > I'm not seeing why this doesn't work; the top few lines of output are: > > CalifCrk | CalCrk | 1996-10-18 | 188 > CalifCrk | CalCrk | 1996-08-23 | 183 > CalifCrk | CalCrk | 1996-07-29 | 201 > CalifCrk | CalCrk | 1996-09-27 | 185 > > when what I want is only the third line. > > A clue to the correct syntax is solicited. I'm sure it's something simple > that I'm just not seeing. remove the sample_date the group by and the select list. by having it in there you are asking for the max for each specific sample date. merlin -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
