From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Eisentraut <peter_e@gmx.net>
Cc: pgsql-sql@postgresql.org, Daniel CAUNE <d.caune@free.fr>
Subject: Re: SQL92 compliance
Date: Wed, 23 Aug 2006 13:40:16 -0400
Message-ID: <22448.1156354816@sss.pgh.pa.us> (raw)
In-Reply-To: <200608231811.48538.peter_e@gmx.net>
References: <000301c6c655$0e3a0100$0b00a8c0@tedy>
<200608231811.48538.peter_e@gmx.net>
Peter Eisentraut <peter_e@gmx.net> writes:
> Am Mittwoch, 23. August 2006 03:40 schrieb Daniel CAUNE:
>> Is AS in "SELECT my_column AS my_name FROM my_table" mandatory to be SQL92
>> compliant?
> No. I have a patch at
> <http://developer.postgresql.org/~petere/select-without-as/select-without-as.patch;
> that fixes this at least for 7.4.
I think it's a big stretch to say that that patch fixes it, since it
only allows an AS-less target expression to be c_expr rather than
a_expr as it ought to.
The problem is really insoluble given that we allow user-defined
postfix operators: is "SELECT x ~~ y" meant to be an infix operator
with arguments x and y, or a postfix operator with argument x and
a column label y?
When this has come up in the past, we've always concluded that
compliance with this not-very-well-thought-out detail of the spec
is not worth the price of giving up postfix operators.
Even if we were willing to do that, I think we'd also have to give
up using bison to generate the parser :-( because some constructs
would require more than one-token lookahead.
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, peter_e@gmx.net, d.caune@free.fr
Subject: Re: SQL92 compliance
In-Reply-To: <22448.1156354816@sss.pgh.pa.us>
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