The following bug has been logged online:
Bug reference: 1453
Logged by:
Email address: m(dot)woehling(at)barthauer(dot)de
PostgreSQL version: 8.0.0
Operating system: Windows 2000
Description: NULLs in UNION query
Details:
The following query should not raise an error ("ERROR: UNION types text and
integer cannot be matched"):
SELECT NULL AS Test
UNION ALL SELECT NULL
UNION ALL SELECT 0