Am 08.02.2016 um 20:32 schrieb Vitaly Burovoy: > On 2/8/16, Adrian Klaver <adrian.klaver@xxxxxxxxxxx> wrote: >> On 02/08/2016 11:05 AM, Johannes wrote: >>> 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; >>> >>> Best regards Johannes >> >> Based on rough guess of the above, without seeing actual table schemas: >> >> select id, t0.col1, t1.col1, col2, ... from t0 JOIN t1 ON t0.id = >> t1.t0_id where id = (select max(id) from t0 where col1 = value1 and col2 >> = value2 and ...); > > I don't think it is a good solution because it leads to copying > columns from the t0 which is wasting net traffic and increasing > complexity at the client side. Moreover it works iff t0 returns only > one row. I had same doubts. CTE would be first class, if it was be reusable for other statements. Johannes
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