The following bug has been logged online:
Bug reference: 6079
Logged by: Renat
Email address: renat.nasyrov@itv.ru
PostgreSQL version: 9.0.4
Operating system: Windows
Description: Wrong select result
Details:
INPUT:
create table foo (
id bigint not null,
date_to timestamp without time zone,
CONSTRAINT foo_pkey PRIMARY KEY (id)
);
CREATE INDEX foo_date_to_index
ON foo
USING btree
(date_to)
insert into foo (id, date_to) values (1, now());
insert into foo (id, date_to) values (2, NULL);
select * from foo where date_to is null and date_to > '2011-01-01'
Expected: 0 rows
But: it return 1 row with id=2
If we will replace foo_date_to_index to:
CREATE INDEX foo_date_to_index
ON foo
USING btree
(date_to)
WHERE date_to is NOT NULL
Then:
SELECT * FROM foo where date_to is null and date_to > '2011-01-01'
Return: 0 rows
Please explain for me what happens?
