Re: sql help-select sum of 2 fields in flat file

["David Bulog" <d2ba@xxxxxxxxxx>]

Hence the power of the AS/400, SQL Server will never be able to get at
the raw data like this
Dave

----- Original Message -----
From: "Joe Pluta" <joepluta@PlutaBrothers.com>
To: <midrange-l@midrange.com>
Sent: Monday, January 14, 2002 10:37 AM
Subject: RE: sql help-select sum of 2 fields in flat file


> > From: Jim Franz
> >
> > this sql is in a rpg inquiry program over ar invoice file. The problem
is
> > performance. Over a million record file, so I can't read all records,
> > summing the 2 fields in each record.
>
> Jim, as far as I know, no matter what you do, that's exactly what is going
> to happen - whether it's SQL or RPG or MI, in order to select or not
select
> a record, SOMEBODY will have to read the record, sum the values and decide
> whether to process the record.
>
> While it may be a littler faster under the covers of SQL because (from
what
> I understand) the SQL stays "under the MI layer" while reading the
records,
> at some point you still have to fetch every one of those 2,000,000
records.
>
> If you can't touch the database, then add an extension file that has just
> the record key and the sum of the two fields.  And if you can't touch the
> program that updates the file, then add a trigger to the file that in turn
> updates the extension file.  Either way will outperform the SQL approach,
> probably by orders of magnitude.
>
> If you have a large number of records and a fixed selection criteria, then
> please use the database where it is at its best: logical views.
>
> Joe Pluta
> www.plutabrothers.com
>
>
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