----- Original Message -----
From: "Bruce Momjian" <pgman@candle.pha.pa.us>
To: "elein" <elein@varlena.com>
Cc: "Jan Wieck" <JanWieck@Yahoo.com>; "Vincent Hikida"
<vhikida@inreach.com>; <pgsql-general@postgresql.org>
Sent: Thursday, July 24, 2003 5:35 PM
Subject: Re: Fw: [GENERAL] Is SQL silly as an RDBMS<->app interface?
>
> Yes, it was more powerful because you could do aggregates in the query
> independent of the results returned by the query.
>
> The 'by' feature of aggregates always confused me because it would
> modify the aggregate WHERE clause (that was independent of the outer
> query) and restrict the aggregate to only process rows where the outer
> query's column value matched the same column's value in the aggregate.
>
Actually, I used a hierarchical/relational DBMS called Nomad in 1981. If I
understand Bruce, Nomad could do the same thing. I could aggregate at
different levels in the same query. Each aggregate created a break and I
could add whatever code I wanted at the level. I could also refer to any
level of aggregate in the rest of the query. I could also refer to any level
aggregate in the rest of the code. This meant that I could for example
calculate what percentage of the total the individual row was. The only
problem was that I could only join two tables at a time so if I wanted to
join several tables I had to have several statements. Each statement created
an intermediate table which was easy to refer to in subsequent statements.
Vincent