On Mon, Oct 10, 2011 at 6:14 PM, Scott Marlowe <scott.marlowe@xxxxxxxxx> wrote: > On Mon, Oct 10, 2011 at 4:17 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. Correction. 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 order by 4 desc limit 1; -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
