Programming languages, perhaps, but clearly not uncommon in SQL ... Informix certainly allows a column to be of type
booleanbut with a value of NULL for given rows (unless precluded by a not-null constraint). Should we question
integers,which can be positive, negative, or -- gasp ! -- NULL ?
I don't see what your point is. That SQL is wrong ? Or that SQL is not "C" ? Or that SQL is not a "programming
language"?
"?Que purposa sirve tanto comedia ? Quien inventan tab miseria ?"
Greg Williamson
DBA
GLobeXplorer LLC
-----Original Message-----
From: sad [mailto:sad@bankir.ru]
Sent: Wed 6/23/2004 10:01 PM
To: pgsql-sql@postgresql.org
Cc:
Subject: Re: [SQL] feature request ?
On Wednesday 23 June 2004 21:12, you wrote:
> Sad,
>
> > since BOOL expression has three possible values: TRUE,FALSE,NULL
> > plpgsql IF control structure should have three alternate blocks:
> > THEN,ELSE,NULL
> >
> > shouldn't it ?
>
> No, why?
>
> How would you construct a tri-valued IF/THEN? Doesn't seem too likely
> to me, as well as being different from every other programming language in
> existance ...
Three valued BOOLEAN is already different "from every other programming
language in existance"
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