The following bug has been logged on the website: Bug reference: 7644 Logged by: Bernhard Reutner-Fischer Email address: rep.dot....@gmail.com PostgreSQL version: 9.1.6 Operating system: debian Description:
Hi, According to http://www.postgresql.org/docs/9.1/static/typeconv-union-case.html i think that these 2 (separate?) issues are bugs(?) 1) select distinct on (bug) bug from ( select * from (select 'string one' AS bug from generate_series(0,1)) s1 UNION select * from (select 'string two' bug from generate_series(0,0)) s2 ) x ; ERROR: could not determine which collation to use for string comparison HINT: Use the COLLATE clause to set the collation explicitly. When casting the return value of the union to :text _explicitly_ it works as expected: select distinct on (bug) bug from ( select * from (select 'string one'::text AS bug from generate_series(0,1)) s1 UNION select * from (select 'string two' bug from generate_series(0,0)) s2 ) x ; bug ------------ string one string two (2 rows) 2) select distinct on (bug) bug from ( select * from (select 'string one' AS bug from generate_series(0,1)) s1 UNION select * from (select 'string two' bug) s2 ) x ; ERROR: failed to find conversion function from unknown to text In this case, however, using a "Result" fails to implicitly typecast to :text, i.e. casting the return value of the first return value of the union to :text explicitly does _not_ work: select distinct on (bug) bug from ( select * from (select 'string one'::text AS bug from generate_series(0,1)) s1 UNION select * from (select 'string two' bug ) s2 ) x ; ERROR: failed to find conversion function from unknown to text What am i missing or doing wrong? thanks and cheers, -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
