handling of COUNT(record) vs IS NULL
От
Sam Mason
Тема
handling of COUNT(record) vs IS NULL
Дата
Msg-id
20080128155943.GR18990@frubble.xen.chris-lamb.co.uk
Список
Дерево обсуждения
handling of COUNT(record) vs IS NULL Sam Mason <sam@samason.me.uk>
Re: handling of COUNT(record) vs IS NULL Tom Lane <tgl@sss.pgh.pa.us>
Re: handling of COUNT(record) vs IS NULL Sam Mason <sam@samason.me.uk>
Re: handling of COUNT(record) vs IS NULL Gregory Stark <stark@enterprisedb.com>
Hi,
I've just noticed that the handling of COUNT(record) and (record IS
NULL) aren't consistent with my understanding of them. If I run the
following query:
SELECT
NULL IS NULL, COUNT( NULL ),
(NULL,NULL) IS NULL, COUNT((NULL,NULL));
The IS NULL checks both return TRUE as I'd expect them to, but the
second count doesn't return 0.
The Comparison Operator docs[1] describe the behaviour of IS NULL
changing, with respect to records, in version 8.2. Is count still
exhibiting the old behaviour?
Sam
[1] http://www.postgresql.org/docs/8.2/static/functions-comparison.html
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