On 2/8/16, Johannes <jotpe@xxxxxxxxx> wrote: > Am 08.02.2016 um 20:15 schrieb David G. Johnston: >> On Mon, Feb 8, 2016 at 12:05 PM, Johannes <jotpe@xxxxxxxxx> wrote: >> >>> Hi, >>> >>> is there a best practice to share data between two select statements? >>> >>> Imaging following situation: I want to receive two result sets from two >>> tables, referring to a specific id from table t0 AND I try not to query >>> for that specific id a second time. >>> >>> Table t0 returns 1 row and table t1 returns multiple rows. >>> >>> begin; >>> select id, col1, col2, ... from t0 where id = (select max(id) from t0 >>> where col1 = value1 and col2 = value2 and ...); >>> select col1 from t1 where t0_id = (select max(id) from t0 where col1 = >>> value1 and col2 = value2 and ...); >>> commit; >> >> >> Please confirm: >> >> You want the result of "SELECT max(id) FROM t0" to be used in the >> second >> query without having to recompute it? > > Yes. > >> What client are you using to execute these statements? > > JDBC. I execute both statements at once and iterate through the resultsets. > > Johannes Hmm. Could you clarify why you don't want to pass id from the first query to the second one: select col1 from t1 where t0_id = value_id_from_the_first_query -- Best regards, Vitaly Burovoy -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
