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From: Stefan Weiss <spaceman@foo.at>
Organization: Foo Orbital Operations
To: pgsql-sql@postgresql.org
Subject: Re: FW: "=" operator vs. "IS"
Date: Tue, 29 Jun 2004 01:02:24 +0200
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Re,

thanks for all the replies.

On Tuesday, 29 June 2004 00:17, Dmitri Bichko wrote:
> As far as TRUE and FALSE go, from what I know you can use = to compare
> them with boolean columns, unless I misunderstood your question.

Sorry, I must have remembered that incorrectly, or maybe I've been
thinking of a different DBMS or version. "table.col = TRUE" seems to
work fine for me now.

I understand that the result of "(anything) = NULL" will always NULL,
so it's a waste of breath. That's where the "IS" operator(?) comes in,
which allows for comparison with NULL. The only question left is why
"IS" can also be used to compare with the TRUE/FALSE keywords (when a
simple "=" should be sufficient here), but not to compare two boolean
columns.


cheers,
stefan


BTW, I really liked Mike's explanation that "it just IS" ;-)