Re: Simple SQL quetsion

Bill Bearden wrote:
>
> A true primary key can't be null. If this is truly a primary key, select
> count(*) should be the same as selecting count(distinct primary_key).
>
> Here is one way to check for distinct composite key...
>
> select count(distinct to_char(organization_id) +
> to_char(inventory_item_id)) k
> from inv.mtl_system_items;
>
> Bill Bearden
> Consultant
> Nimrod Oren <orenn_at_inter.net.il> wrote in article
> <339F1A31.3242EF0_at_inter.net.il>...
> > I'm using the rule-based optimizer and I try to get the number of
> > records from a table with a composite primary-key.
> > Select count(*) does a full table scan. Is there a way to count the
> > occurrences of the primary key (hopefully without hints)?
> >
> >

If it's a primary key, you don't need to specify distinct! Also I suspect the "+" in you answer should be the concatenation character. You could also use concat(organization_id,inventory_item_id).

Chrysalis. Received on Thu Jun 12 1997 - 00:00:00 CDT