nicer examples for aggregate calls
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/14/tutorial-agg.html
Description:
currently, all of the examples are very simple, like
SELECT city, max(temp_lo)
FROM weather
WHERE city LIKE 'S%' -- (1)
GROUP BY city
HAVING max(temp_lo) < 40;
this example would be more complex and would allow users to search for
clause "filter":
Finally, if we only care about cities whose names begin with “S” and we want
to calculate the number of observations in each city with temp_lo over 30,
we might do:
SELECT city, max(temp_lo), count(*) filter (temp_lo>30),
FROM weather
WHERE city LIKE 'S%' -- (1)
GROUP BY city
HAVING max(temp_lo) < 40;
On Sat, Oct 23, 2021 at 01:51:48PM +0000, PG Doc comments form wrote:
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/14/tutorial-agg.html
Description:currently, all of the examples are very simple, like
SELECT city, max(temp_lo)
FROM weather
WHERE city LIKE 'S%' -- (1)
GROUP BY city
HAVING max(temp_lo) < 40;this example would be more complex and would allow users to search for
clause "filter":Finally, if we only care about cities whose names begin with “S” and we want
to calculate the number of observations in each city with temp_lo over 30,
we might do:SELECT city, max(temp_lo), count(*) filter (temp_lo>30),
FROM weather
WHERE city LIKE 'S%' -- (1)
GROUP BY city
HAVING max(temp_lo) < 40;
Good idea. We didn't support FILTER at the time this query was added.
Here is a patch which adds it.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
Indecision is a decision. Inaction is an action. Mark Batterson
Attachments:
filter.difftext/x-diff; charset=us-asciiDownload+7-5
On Wed, Aug 17, 2022 at 12:20:10PM -0400, Bruce Momjian wrote:
On Sat, Oct 23, 2021 at 01:51:48PM +0000, PG Doc comments form wrote:
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/14/tutorial-agg.html
Description:currently, all of the examples are very simple, like
SELECT city, max(temp_lo)
FROM weather
WHERE city LIKE 'S%' -- (1)
GROUP BY city
HAVING max(temp_lo) < 40;this example would be more complex and would allow users to search for
clause "filter":Finally, if we only care about cities whose names begin with “S” and we want
to calculate the number of observations in each city with temp_lo over 30,
we might do:SELECT city, max(temp_lo), count(*) filter (temp_lo>30),
FROM weather
WHERE city LIKE 'S%' -- (1)
GROUP BY city
HAVING max(temp_lo) < 40;Good idea. We didn't support FILTER at the time this query was added.
Here is a patch which adds it.
Patch applied back to PG 10. Thanks.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
Indecision is a decision. Inaction is an action. Mark Batterson