From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | Hitoshi Harada <umi(dot)tanuki(at)gmail(dot)com> |
Cc: | Marko Tiikkaja <marko(dot)tiikkaja(at)cs(dot)helsinki(dot)fi>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: top-level DML under CTEs |
Date: | 2010-09-15 03:22:44 |
Message-ID: | 24626.1284520964@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers pgsql-rrreviewers |
Hitoshi Harada <umi(dot)tanuki(at)gmail(dot)com> writes:
> 2010/9/15 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
>> Why is it so difficult to do this correctly?
> Because INSERT INTO ... (SELECT|VALUES) is already a collection of
> kludge (as comments say). It was possible to parse the two WITHs
> separately, but it results in ambiguous naming issue;
> parseWithClause() asserts there's only one WITH clause in the Stmt and
> detects duplicated CTE name in it.
Well, I would think that the no-duplication rule applies to each WITH
list separately, not both together. If you do something like
with t1 as (select * from foo)
select * from
(with t2 as (select * from foo)
select * from t1, t2) ss;
there's no expectation that the WITH clauses can't both define the same
name.
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Robert Haas | 2010-09-15 03:22:58 | Re: knngist - 0.8 |
Previous Message | Tom Lane | 2010-09-15 02:47:10 | Re: elog during holding a spinlock is safe? |
From | Date | Subject | |
---|---|---|---|
Next Message | Hitoshi Harada | 2010-09-15 04:38:17 | Re: top-level DML under CTEs |
Previous Message | Hitoshi Harada | 2010-09-15 01:15:12 | Re: top-level DML under CTEs |