Re: Incremental sum ?

On Fri, Jun 22, 2001 at 12:58:46PM -0400, Tom Lane wrote:
> "Ross J. Reedstrom" <reedstrm(at)rice(dot)edu> writes:
> > And here's the working example: not the need to GROUP BY, and <=
> > to get the current payment.
>
> > select cust_id,invoice_id,val,paid, (select (sum(val) - sum(paid))
> > from invoices_not_paid where cust_id= i.cust_id and invoice_id <=
> > i.invoice_id group by cust_id) as balance from invoices_not_paid i;
>
> Actually I think you could leave off the inner GROUP BY --- won't there
> always be exactly one group, since only one value of inner cust_id is
> selected?

Sure enough, it works fine. My internal rule: "can't use aggregates
without a group by" mis-fired.

Ross