From: | Don Baccus <dhogaza(at)pacifier(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Thomas Lockhart <lockhart(at)alumni(dot)caltech(dot)edu>, Magnus Hagander <mha(at)sollentuna(dot)net>, Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: comparing rows |
Date: | 2000-08-03 14:37:17 |
Message-ID: | 3.0.1.32.20000803073717.014d7100@mail.pacifier.com |
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Lists: | pgsql-hackers |
At 10:23 AM 8/3/00 -0400, Tom Lane wrote:
>Don Baccus <dhogaza(at)pacifier(dot)com> writes:
>> If foo = NULL is illegal, doesn't this make it rather difficult to
>> say things like table1.i = table2.i for tables that contain NULLs
>> in column i?
>
>Thomas is not saying that the *operation* is illegal. His point is
>purely a syntactic one: SQL92 allows the keyword "NULL" only in certain
>specified contexts, and out on its own as a component of an arithmetic
>expression ain't one of them.
I misunderstood, didn't check for the use of the literal, just the
semantics of the operations.
>As far as I can see, allowing NULL as a general-purpose literal is a
>perfectly reasonable spec extension that *everybody* does, including us.
>Thomas may be the only person anywhere who is bothered by it ;-)
Thomas, do you have a reference into the standard?
- Don Baccus, Portland OR <dhogaza(at)pacifier(dot)com>
Nature photos, on-line guides, Pacific Northwest
Rare Bird Alert Service and other goodies at
http://donb.photo.net.
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