From: | mlw <markw(at)mohawksoft(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Hackers List <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: SET variables |
Date: | 2001-05-13 12:31:25 |
Message-ID: | 3AFE7E9C.1E28ECAE@mohawksoft.com |
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Lists: | pgsql-hackers |
Tom Lane wrote:
> mlw <markw(at)mohawksoft(dot)com> writes:
> > Would it be possible to allocate varibles that can be addressed with SET?
>
> And what would you do with them?
>
> There is a simple variable facility in psql these days, if that helps.g
I was thinking more like:
create variable fubar ;
set fubar = select max(column) from table;
select * from table where column = :fubar;
Obviously this is a very simple example. I guess I am asking for something
analogous to temporary tables, but on a single datum level.
I like the way psql does it, but it would be better to have this available in
the native query language.
This is similar to a feature which Oracle has. It is mainly to avoid hitting
the query planner. Oracle caches query execution instructions, and using a
variable is a way to reuse cached queries with different data.
Being able to set variables and use them in queries may help some people port
from Oracle to Postgres.
BTW I am also working on the impression that a view is more efficient than
reissuing a complex query. Or is there no difference?
>
>
> regards, tom lane
>
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