On 24 June 2013 04:29, Josh Berkus <j...@agliodbs.com> wrote: > On 06/23/2013 08:00 PM, Andrew Gierth wrote: >> OK, let's try to cover all the bases here in one go. > >> 1. Stick with "?column?" as a warning flag that you're not supposed to >> be using this without aliasing it to something. > > How do I actually supply an alias which covers both columns? What does > that look like, syntactically? >
There are a number of possible syntaxes: SELECT unnest, "?column?" FROM unnest(ARRAY['x','y']) WITH ORDINALITY; or SELECT unnest.unnest, unnest."?column?" FROM unnest(ARRAY['x','y']) WITH ORDINALITY; unnest | ?column? --------+---------- x | 1 y | 2 (2 rows) SELECT t, "?column?" FROM unnest(ARRAY['x','y']) WITH ORDINALITY AS t; or SELECT t.t, t."?column?" FROM unnest(ARRAY['x','y']) WITH ORDINALITY AS t; t | ?column? ---+---------- x | 1 y | 2 (2 rows) SELECT val, "?column?" FROM unnest(ARRAY['x','y']) WITH ORDINALITY AS t(val); or SELECT t.val, t."?column?" FROM unnest(ARRAY['x','y']) WITH ORDINALITY AS t(val); val | ?column? -----+---------- x | 1 y | 2 (2 rows) SELECT val, ord FROM unnest(ARRAY['x','y']) WITH ORDINALITY AS t(val, ord); or SELECT t.val, t.ord FROM unnest(ARRAY['x','y']) WITH ORDINALITY AS t(val, ord); val | ord -----+----- x | 1 y | 2 (2 rows) My suggestion was to replace "?column?" with ordinality wherever it appears above, for the user's convenience, but so far more people prefer "?column?" as a way of indicating that you're supposed to provide an alias for the column. If that's what people prefer, I don't mind --- it's still going to be a very handy new feature. Regards, Dean -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
