Re: "=" operator vs. "IS"
От | Michael A Nachbaur |
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Тема | Re: "=" operator vs. "IS" |
Дата | |
Msg-id | 200406281528.08526.mike@nachbaur.com обсуждение исходный текст |
Ответ на | "=" operator vs. "IS" (Stefan Weiss <spaceman@foo.at>) |
Ответы |
Re: "=" operator vs. "IS"
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Список | pgsql-sql |
On June 28, 2004 03:02 pm, Stefan Weiss wrote: > I'm just curious - why is it not possible to use the "=" operator to > compare values with NULL? I suspect that the SQL standard specified > it that way, but I can't see any ambiguity in an expression like "AND > foo.bar = NULL". Is it because NULL does not "equal" any value, and the > expression should be read as "foo.bar is unknown"? Or is there something > else I'm missing? As far as I have been able to tell, it is one of those quirks about SQL that you shouldn't bother trying to understand. It just IS. <rimshot/> -- Michael A. Nachbaur <mike@nachbaur.com> http://nachbaur.com/pgpkey.asc
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