Hi, Union with NULL error persists without the corresponding patch. Here is the output from postgres without the patch:
SELECT a FROM (SELECT 1 a) foo UNION SELECT a FROM (SELECT NULL a) foo2; ERROR: failed to find conversion function from unknown to integer It is thrown from parse_coerce.c:coerce_type method. I will try to dig deep on it. Regards, Kerem KAT On Thu, Oct 27, 2011 at 15:45, Erik Rijkers <e...@xs4all.nl> wrote: > (pgsql 9.2devel (25 oct) with your latest CORRESPONDING patch; > linux x86_64 GNU/Linux 2.6.18-274.3.1.el5) > > Hi, > > here is another peculiarity, which I think is a bug: > > -- first without CORRESPONDING: > > $ psql -Xaf null.sql > select 1 a , 2 b > union all > select null a, 4 b ; > a | b > ---+--- > 1 | 2 > | 4 > (2 rows) > > -- then with CORRESPONDING: > > select 1 a , 2 b > union all > corresponding > select null a, 4 b ; > psql:null.sql:9: ERROR: failed to find conversion function from unknown to > integer > > > If the null value is in a table column the error does not occur: > > drop table if exists t1; create table t1 (a int, b int); insert into t1 > values (1,2); > drop table if exists t2; create table t2 (a int, b int); insert into t2 > values (null,2); > select a,b from t1 > union all > corresponding > select a,b from t2 ; > a | b > ---+--- > 1 | 2 > | 2 > (2 rows) > > > I'm not sure it is actually a bug; but it seems an unneccessary error. > > > thanks, > > Erik Rijkers > > -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers