I know I can join using the pk, but in oracle using the rowid is faster so I wanted to know, if this is possible in PostgreSQL as well.
Dirk -- Dirk Mika Software Developer mika:timing GmbH Strundepark - Kürtener Str. 11b 51465 Bergisch Gladbach Germany fon +49 2202 2401-1197 dirk.m...@mikatiming.de www.mikatiming.de AG Köln HRB 47509 * WEEE-Reg.-Nr. DE 90029884 Geschäftsführer: Harald Mika, Jörg Mika ## How2Use ## the ChampionChip by mika:timing ## https://youtu.be/qfOFXrpSKLQ Am 01.07.19, 11:36 schrieb "Thomas Kellerer" <spam_ea...@gmx.net>: > I come from the Oracle world and am trying to convert some queries to > PostgreSQL syntax. One of these queries is a MERGE statement, which I > converted into an UPDATE SET FROM WHERE construct. In the original > query I use the pseudo column ROWID to match a source row with a > target row. > > In the PostgreSQL version I use the column ctid for this. The above query becomes: > > *UPDATE*test_large d > *SET* grp = s.grp > *FROM* (*SELECT* ctid, test_large.* > *FROM* test_large > *WHERE* grp = 1) s > *WHERE* d.ctid = s.ctid; Why don't you join on the primary key column? The ctid comparison is typically quite slow. Thomas
