On 2011-04-20, Saulo Venâncio <saulo.venan...@gmail.com> wrote: > --bcaec52e65e9b2f22304a15f3840 > Content-Type: text/plain; charset=ISO-8859-1 > Content-Transfer-Encoding: quoted-printable > > Hi guys, > I need your help. > I have a table called medidas, in this table i have some ocurrences that ha= > s > id_medida(primary key) id_ponto (sec_key) and also datetime field as > timestamp. > i would like to know from a set of idpontos, e.g. 10,11,23,24.... how can i > get the most recent date that is common to all?? > for example, if idponto das date 2011-02-03 but none of others have this > date in the db i dont want this. i want one common for all.. > thanks.
the trick seems to be to GROUP BY datetime and to use a HAVING clause to reject the unwanted groups using count(distinct()) to ensure coverage of the list. -- a table create temp table medidas(id_medida serial,id_ponto integer,datetime timestamp); -- some test data. insert into medidas (id_ponto,datetime) select floor(random()*30+1),('today'::timestamp + floor(generate_series(0,100000)/10)*'1s'::interval); -- the query: -- note you need to paste the list of number in two different places -- in the query, postgres only counts the length once. select datetime from medidas where id_ponto in (10,11,23,24,27) group by datetime having count(distinct(id_ponto)) = array_length( array[10,11,23,24,27],1) order by datetime desc limit 1; -- confirmation select * from medidas where datetime = ( select datetime from medidas where id_ponto in (10,11,23,24,27) group by datetime having count(distinct(id_ponto)) = array_length(array[10,11,23,24,27],1) order by datetime desc limit 1 ) order by id_ponto; what's this for? Are you looking at keno results to see how recently your pick would have won? -- ⚂⚃ 100% natural -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql