Re: NULL != text ?
| От | Michael Fuhr |
|---|---|
| Тема | Re: NULL != text ? |
| Дата | |
| Msg-id | 20051020144512.GA78854@winnie.fuhr.org обсуждение |
| Ответ на | Re: NULL != text ? (Michael Glaesemann <grzm@myrealbox.com>) |
| Ответы |
Re: NULL != text ?
|
| Список | pgsql-general |
On Thu, Oct 20, 2005 at 03:57:41PM +0900, Michael Glaesemann wrote: > On Oct 20, 2005, at 15:44 , Michael Fuhr wrote: > > expression IS DISTINCT FROM expression > > > > For non-null inputs this is the same as the <> operator. However, > > when both inputs are null it will return false, and when just one > > input is null it will return true. Thus it effectively acts as > > though null were a normal data value, rather than "unknown". > > Interesting! Thanks, Michael. You don't happen to know off the top of > your head if that's standard SQL, do you? IS DISTINCT FROM is defined in SQL:1999 and SQL:2003. -- Michael Fuhr
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