On 10/10/2011 05:52 PM, Rich Shepard wrote:
> On Mon, 10 Oct 2011, John R Pierce wrote:
>
>> the complication is, there can be more than one date with the same
>> maximum
>> value, so such a query would be ambiguous, or it would return multiple
>> rows.
>
> John,
>
> The likelihood of that is d
On Mon, Oct 10, 2011 at 4:17 PM, Rich Shepard 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
On Mon, Oct 10, 2011 at 6:14 PM, Scott Marlowe wrote:
> On Mon, Oct 10, 2011 at 4:17 PM, Rich Shepard
> 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:
>>
>>
On Mon, 10 Oct 2011, John R Pierce wrote:
the complication is, there can be more than one date with the same maximum
value, so such a query would be ambiguous, or it would return multiple
rows.
John,
The likelihood of that is diminishingly small.
Thanks,
Rich
--
Sent via pgsql-general ma
On 10/10/11 3:45 PM, Rich Shepard wrote:
As I asked Merlin, what is necessary to get the date that maximum
quantity
was recorded? A nested SELECT?
the complication is, there can be more than one date with the same
maximum value, so such a query would be ambiguous, or it would return
multip
On Mon, 10 Oct 2011, Henry Drexler wrote:
you are also grouping by sample date, those are the largest values for the
criteria you have set out in the group by.
Henry,
As I asked Merlin, what is necessary to get the date that maximum quantity
was recorded? A nested SELECT?
Thanks,
Rich
--
On Mon, 10 Oct 2011, Merlin Moncure wrote:
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,
That tells me the max quant but not on what date. Do I write a nested
SELECT to get that, too?
Thanks
for instance
CalifCrk| CalCrk | 1996-10-18 |188
CalifCrk| CalCrk | 1996-08-23 |183
CalifCrk| CalCrk | 1996-07-29 |201
CalifCrk| CalCrk | 1996-09-27 |185
188 is the biggest number for 1996-10-18 calcrk califcrk, and so on down
you are also grouping by sample date, those are the largest values for the
criteria you have set out in the group by.
On Mon, Oct 10, 2011 at 6:17 PM, Rich Shepard wrote:
> I'm trying to query the table to extract the single highest value of a
> chemical by location and date. This statement gi
On Mon, Oct 10, 2011 at 5:17 PM, Rich Shepard 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
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
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