NULL cannot automatically be casted to every other type

[monetdb-team]

Date: 2010-07-07 15:29:53 +0200
From: @grobian
To: SQL devs <>
Version: 11.9.5 (Apr2012-SP1) [obsolete]
CC: charnik, @njnes

Last updated: 2012-06-19 11:20:12 +0200

Comment 14252

Date: 2010-07-07 15:29:53 +0200
From: @grobian

create table skyboom (i int, ts timestamp);

select i as boom1, ts as boom2 from skyboom
union
select NULL as boom1, NULL as boom2;

The result is:
types char(0,0) boom1(str) and int(32,0) (int) are not equal

and if we could do an explicit CAST(NULL AS int) instead, it would complain about boom2.

This is a generic problem, as NULL gets typed as char, while it should be casted to any type required, unless explicitly casted to a type. Perhaps a NULL type is required.

Comment 14841

Date: 2010-08-30 09:23:20 +0200
From: @sjoerdmullender

The Jun2010-SP2 version has been released.

Comment 15683

Date: 2011-03-28 17:36:31 +0200
From: @sjoerdmullender

The Mar2011 version has been released.

Comment 16035

Date: 2011-07-29 11:00:03 +0200
From: @sjoerdmullender

Apr2011-SP2 has been released.

Comment 16273

Date: 2011-09-16 15:10:38 +0200
From: @sjoerdmullender

The Aug2011 version has been released.

Comment 17261

Date: 2012-05-16 22:49:31 +0200
From: @njnes

Changeset 3012edaf1396 made by Niels Nes niels@cwi.nl in the MonetDB repo, refers to this bug.

For complete details, see http//devmonetdborg/hg/MonetDB?cmd=changeset;node=3012edaf1396

Changeset description:

added test for bug #2594

Comment 17262

Date: 2012-05-16 22:51:14 +0200
From: @njnes

implemented default NULL as type ANY.