Tom Lane wrote:
Mike Mascari <[EMAIL PROTECTED]> writes:I curious if any of the rewriting of EXISTS and NOT EXISTS would address the problem described by Date:
That should read "I'm curious"...
From what I've read of Date's so far, I think he'd like to junk SQL altogether.http://www.firstsql.com/iexist.htmWe are not here to redefine the SQL spec ... and especially not to eliminate its concept of NULL, which is what Date would really like ;-)
Okay. I knew there was talk in the past that IN be rewritten as EXISTS, which is not what you propose doing, but would have exposed the odd behavior NOT EXISTS exhibits according to the SQL spec. I was also curious to know which path PostgreSQL development prefers to take when the SQL spec and the Relational Model part ways, as they often do. Maybe someday RedHat will have a voting member on the ANSI X3H2/NCITS committee. ;-)The above-quoted screed is based on a claimed logical equivalence between NOT EXISTS() and NOT IN() that is just plain wrong when you consider the possibility of NULLs. Rather than "FirstSQL correctly processes this query", you should read "FirstSQL deliberately violates the SQL spec". (There may be grounds to argue that the spec behavior could be improved, but that's an argument to be making to the standards committee, not here.)
Mike Mascari
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