Friday, February 25, 2011, 12:53:08 AM you wrote: > select distinct on (a, b, c) > a, b c, time_stamp, value Without the comma, you declare 'b AS c' > from data > order by a, b, c, time_stamp desc; > The output produced is the same as this query: > select distinct on (a, b) > a, b, time_stamp, value > from data > order by a, b, time_stamp desc; the 'c' is optimized away, since it is an alias for b, and thus redundant for the distinct. > Not sure if this is considered a parser bug or not, but it feels slightly > odd not to get an error. No error, just plain SQL :-) -- Jochen Erwied | home: jochen@xxxxxxxxx +49-208-38800-18, FAX: -19 Sauerbruchstr. 17 | work: joe@xxxxxxxxxxxxxxx +49-2151-7294-24, FAX: -50 D-45470 Muelheim | mobile: jochen.erwied@xxxxxxxxxxx +49-173-5404164 -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
