Re: WHERE IN query

From: James <james_lorenzen_at_allianzlife.com>
Date: Thu, 22 Apr 1999 13:12:20 GMT
Message-ID: <7fn77f$c3m$1@nnrp1.dejanews.com>

Response is in line.
In article <371F0F79.BDAEC959_at_vnl.nl>,
Frank van Bortel <f.van.bortel_at_vnl.nl> wrote:
> Joerg Leute wrote:
>
> > Hi everybody
> >
> > Isn't it possible to extend a WHERE IN query over 2 columns - first column
> > is number and second is char) like
> >
> > SELECT * FROM TABLE1 WHERE (ID, NAME) IN (SELECT ID_2, NAME_2 FROM TABLE2)
> >
>
> No - how would I (or the rdbms) need to read this? Is this an AND or an OR -

The parens present the columns as a single value, it is an AND condition. IE "WHERE (id and name) are IN (SELECT ID-2 and NAME_2 FROM TABLE2)" Both must match to return a record.

> what about
> NULLS for ID or NAME?

NULLS are treated as NULLS, unknown, not equal to anything, even another NULL and not unequal to anything.

> use the AND, OR and outer joins to resolve all that
> --
> Met vriendelijke groet,
> kind regards,
>
> Frank van Bortel
> Technical consultant Oracle
> V&L Informatica BV
> -----------------------------------------------
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