On Mon, Oct 10, 2011 at 5:17 PM, Rich Shepard <rshepard@appl-ecosys.com> 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
