Re: How to always run UPDATE FROM despite missing records in the source table?

Thank you Adrian -

On Fri, Jan 11, 2019 at 4:55 PM Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
wrote:

> On 1/11/19 4:50 AM, Alexander Farber wrote:
> > https://www.db-fiddle.com/f/22jfWnsvqD8hVeFPXsyLbV/0
>
> Why not put a test for the block in the function and then use different
> UPDATE's depending on the result?
>

I didn't want to use IF and switch that statement to PL/pgSQL from pure
SQL, so Andrew's answer

UPDATE users u SET
visited = now(),
ip = v.ip,
lat = i.lat,
lng = i.lng
FROM (VALUES ('20.20.20.20'::inet)) v(ip)
LEFT JOIN geoip i ON (v.ip <<= i.block)
WHERE u.uid = 2;

suits me better, even though I wonder what is the (VALUES
('20.20.20.20'::inet)) v(ip) construct there, some temporary table which is
then LEGT JOINed to the geoip table?

Also, Andrew you have been right - with spgist index my queries against
geoip are fast enough, I was looking at the wrong spot in my EXPLAIN
ANALYZE output (the average values are slow, I am going to cache them soon)

Regards
Alex