RE: Found an example prooving bug
От | Marcin Zukowski |
---|---|
Тема | RE: Found an example prooving bug |
Дата | |
Msg-id | Pine.LNX.4.21.0105032009110.13351-100000@zodiac.mimuw.edu.pl обсуждение исходный текст |
Ответ на | RE: Found an example prooving bug (Piers Scannell <piers.scannell@globecastne.com>) |
Список | pgsql-bugs |
> From my point of view, NULL is neither bigger, nor smaller, you can't > compare it with a number. > So it just comes at the end if you sort at all. Well, I know you can't compare null in, for example, WHERE clause. But if we want to sort data in some way, I would like Postgres to behave in any, but predictable, way. If last of the query execution steps is sorting, null values are always at the end. And it would be OK, but, depending on the query, values in database, and some options (like ENABLE_SORT), null-values are sometimes at the beginning, because it uses order stored in index. Also, for my bug-report Tom Lane replied with some details from SQL92 specs. And my last mail, with an example (I can wrote less complex one) shows, that pgsql doesn't work the way SQL92 says. So, is it compliant with SQL92 standard in this matter or is it not? If it's not, shouldn't that be changed? > (Perhaps you need to take a think about what NULL means in your data. Should > NULL sort as if it's 0?, +infinity?, -infinity? if so why?) As I wrote - any way. But fixed one. To finish this problem - I've changed my program to use -infinity for null values (but I really don't like it :) ). I still think pgsql is not compliant with SQL92, but I'm not the one to decide if it should be changed. Best regards Marcin Zukowski
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