am Sat, dem 18.11.2006, um 23:02:33 +0530 mailte Rajesh Kumar Mallah folgendes: > >select <bigint_column> from <your_table> order by random() limit 1; > > This query will tend to get slower as the table grows because of the > sorting.
Right. > > it possible to get a row from a random offset > how about > > select <bigint_column> from <your_table> limit 1 offset 20000*random() ; For instance, you have a table with only 500 rows and random() returns 0.999? In other words: in think, this is a bad idea, unless you use a constant for the offset-calculation thats not larger than the number of rows in this table. For this, you need this value, but select count(1) from table force a seqscan -> slow. Andreas -- Andreas Kretschmer Kontakt: Heynitz: 035242/47215, D1: 0160/7141639 (mehr: -> Header) GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA http://wwwkeys.de.pgp.net ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
