On Thu, Jan 12, 2006 at 07:51:22PM +0100, Ott? Havasv?lgyi wrote:
> Hi,
>
> If the join is to a primary key or notnull unique column(s), then
> inner join is also ok. But of course left join is the simpler case.
> An example:
Actually, you need both the unique/pk constraint, and RI (a fact I
miss
On Thu, Jan 12, 2006 at 01:35:07PM +0100, Alessandro Baretta wrote:
> Ott? Havasv?lgyi wrote:
> >Hi all,
> >
> >Is PostgreSQL able to throw unnecessary joins?
> >For example I have two tables, and I join then with their primary keys,
> >say type of bigint . In this case if I don't reference to on
Hi,
If the join is to a primary key or notnull unique column(s), then
inner join is also ok. But of course left join is the simpler case.
An example:
create table person (id serial primary key, name varchar not null);
create table pet (id serial primary key, name varchar not null,
person_id int n
On Thu, 2006-01-12 at 11:00, Ottó Havasvölgyi wrote:
> Hi,
>
> I think it would be sufficient only for views. In other cases the
> programmer can optimize himself. But a view can be a join of other
> tables, and it is not sure that all of them are always needed. It all
> depends on what I select f
Hi,
I think it would be sufficient only for views. In other cases the
programmer can optimize himself. But a view can be a join of other
tables, and it is not sure that all of them are always needed. It all
depends on what I select from the view.
This information could even be calculted at view cr
Dear Tom,
Not sure about Otto's exact problem, but he did mention views, and I'd feel
more comfortable if you told me that view-based queries are re-planned based
on actual conditions etc. Are they?
Also, if you find it unlikely (or very rare) then it might be a configurable
parameter. If so
=?ISO-8859-1?Q?Ott=F3_Havasv=F6lgyi?= <[EMAIL PROTECTED]> writes:
> As far as I know SQL Server has some similar feature. It does not join
> if not necessary, more exactly: if the result would be the same if it
> joined the table.
I find it really really hard to believe that such cases arise often
Hi,
As far as I know SQL Server has some similar feature. It does not join
if not necessary, more exactly: if the result would be the same if it
joined the table.
Here is another example:
http://www.ianywhere.com/developer/product_manuals/sqlanywhere/0902/en/html/dbugen9/0468.htm
This would be
Ottó Havasvölgyi wrote:
Hi all,
Is PostgreSQL able to throw unnecessary joins?
For example I have two tables, and I join then with their primary keys,
say type of bigint . In this case if I don't reference to one of the
tables anywhere except the join condition, then the join can be eliminate
