RE: SQL under the covers

[Vern Hamberg <vhamberg@xxxxxxxxxxxxxxxxxxxxxxxxx>]

Thanks, Walden, for saying so well what I was trying to say. There IS no 
"generated" statement per se. The stuff is really all done under the covers.

In this case, DBMON showed that the substituted host variables make the 
statement look like this for the QRFLD = 'QQQ014'

select fhpro, fhonm, fhfamt + fhjamt as qnetfee, 
fhsua3
from frp001
Order by
case
  when 'QQQ104' = 'QQQ104' then fhpro
  when 'QQQ104' = 'QQQ105' then fhonm
  when 'QQQ104' = 'QQQ111' then fhsua3
  else null
end

I tried this, using a file I had with different column names. I don't think 
it sorted - fetched in arrival sequence, AFAIK. Could it be hitting the 
NULL? Is it possible that things don't match because of escalating literals 
to VARCHAR, so the equality test fails?

Reeve, does this actually come out in the sorted order for you? I ran this 
on V5R3, not V5R2. I put the statement intoa program I called REEVE with a 
single 6-character parameter QRFLD.

Thanks
Vern


At 12:49 PM 7/12/2004, you wrote:
> >Looking at the generated SQL code (with the SQL includes, SQLCA, etc.)
> >doesn't tell me much.
>
> It won't. The generated SQL code isn't used to access the data, it's
> used to access the SQL engine. The SQL engine is responsible for
> figuring out how to retrieve that data. You shouldn't see anything in
> the RPG that "understands" how that SQL is run.
>
> The best you can do is run the query in debug, but remember, run the
> query against production data. The "right" way to retrieve a row from a
> test table with 50 rows isn't the "right" way to get a row from the same
> table with 50 million rows.
>
> -Walden
>
> ------------
> Walden H Leverich III
> President & CEO
> Tech Software
> (516) 627-3800 x11
> WaldenL@xxxxxxxxxxxxxxx
> http://www.TechSoftInc.com
>
> Quiquid latine dictum sit altum viditur.
> (Whatever is said in Latin seems profound.)