Обсуждение:
Hi,
I’m trying to work out how to make an update query work with a join in posrgre.
I can write it in normal SQL, but postgre comes up with an error on the first ‘inner join’. The online help (that is not very good) makes it seem like you do not use the ‘inner join’ at all, but just aggregate; but then postgre comes up with an error saying this won’t work either.
Any hints would be most helpful.
The code I started with is:
UPDATE public_consumption_hanson_uk_el_clear INNER JOIN public_consumption_hanson2 ON (public_consumption_hanson_uk_el_clear.supply_day = public_consumption_hanson2.supply_day) AND (public_consumption_hanson_uk_el_clear.supply_band_name = public_consumption_hanson2.supply_band_name) AND (public_consumption_hanson_uk_el_clear.meterreference = public_consumption_hanson2.meter_no) AND (public_consumption_hanson_uk_el_clear.meterpointreference = public_consumption_hanson2.mpan) SET public_consumption_hanson_uk_el_clear.actual_estimate = Min([consumption_hanson2].[actual_estimate]);
Thanks in advance!
On Mon, Jul 12, 2010 at 4:31 AM, Matthew Sleight <matthewsleight@encore-international.net> wrote: > I can write it in normal SQL, but postgre comes up with an error on the > first ‘inner join’. Correct, inner joins in an update statement are violations of the SQL standard and are not supported by PostgreSQL. The following link explains correct syntax that can be used with an update statement: http://www.postgresql.org/docs/9.0/static/sql-update.html > The online help (that is not very good) If it isn't very good, do you have any suggestions on how it can be improved? --SQL compliant syntax UPDATE public_consumption_hanson_uk_el_clear AS A SET acutal_estimate = ( SELECT MIN( C.actual_estimate ) AS minimum_actual_estimate FROM public_consumption_hanson2 AS C WHERE C.supply_day = A.supply_day AND C.supply_brand_name = A.supply_brand_name AND C.meter_no = A.meterreference AND C.mpan = A.meterpiontreference ) AS B( minimum_actual_estimate ); --Postgresql extension syntax UPDATE public_consumption_hanson_uk_el_clear AS A SET acutal_estimate = B.minimum_actual_estimate FROM ( SELECT supply_day, supply_brand_name, meter_no, mpan, MIN( C.actual_estimate ) AS minimum_actual_estimate FROM public_consumption_hanson2 AS C GROUP BY supply_day, supply_brand_name, meter_no ) AS B WHERE B.supply_day = A.supply_day AND B.supply_brand_name = A.supply_brand_name AND B.meter_no = A.meterreference AND B.mpan = A.meterpiontreference ; -- Regards, Richard Broersma Jr. Visit the Los Angeles PostgreSQL Users Group (LAPUG) http://pugs.postgresql.org/lapug