Re: [SQL] HAVING in EXISTS-clause ...

>
> Hello all out there,
>
> > involving aggregate functions as sub-selects in FROM. So it's probably
> > not worth any effort to add more code to a routine that shouldn't exist
> > in the first place; we've got to work on the fundamental problem
>
> What makes me nervous is the fact, that I've seen limitations with
> the length of the sql statements, some hidden problems here and there
> and we want to use PostgreSQL in a research projects the next year
> and we're writing now some oo->rdbms mapper software and therefore
> we produce some "non-typical" statements and see those limitations
> (and perhaps even better: some are not documented).

Nervous or not, Tom is right!

Some people seem to forget that Postgres initially was a
PostQUEL database. After the original Berkeley project
terminated, it became a SQL database and (sometimes) later
called PostgreSQL.

The PostQUEL query language was way simpler than SQL. All the
internal structures of Postgres where optimized to match this
language.

We need to change a detail in the parser/rewriter now, to
meet the needs of our new language. This requires changes not
only in the parser and rewirter, the planner/optimizer and
maybe the executor need changes too. Usually, this kind of
vertical change takes some time in open source projects.

But it doesn't help to continue doing cosmetic changes on the
symptoms. Sometimes you have to attack the initial problems,
and this time is now.

Jan

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