Re: Embedded SQL, first steps -- MIDRANGE-L

I am not as expert on this as I would like, so I use several simple SQLstatements when sometimes more complex might do the task. I am currentlyin V5R1 but learned embedded SQL in V4 something, maybe even V3.

I not know performance, virtually all my embedded SQL runs in some programin JOBQ anyway.

I have some embedded SQL statement to actually get the data, usually usinga CURSOR which is like a step in a loop, I use the same statement outsideof the loop, typically at very beginning or end, in which instead ofactually getting the raw data, the statement is going after MIN(*) MAX(*)range or COUNT(*) instances of whatever the loop going after.

This may not be quite what you looking for, but here's example of me usingCOUNT in an embedded SQL. This is from a program that "inventories" scaleof "problems" me "computer janitor" needs to address.


   *
  C/EXEC SQL
  C+ SELECT COUNT(*) INTO :CNTSQL
  C+ FROM ITH WHERE TPROD
  C+ NOT IN (SELECT IPROD FROM IIM)
  C/END-EXEC
   *

This counts how many inventory history records exist on items that nolonger exist in the item master


You can manipulate the data as it comes in ...
Here's where we add two fields together as they come into RPG from SQL

  C/EXEC SQL
  C+ SELECT (FOD.ORUN+FOD.OMAC) INTO :W7CAL FROM FOD WHERE
  C+ FOD.ODID='OD' AND FOD.OORD=:W7ORD AND FOD.OOPNO=:W7OPNO
  C/END-EXEC

here's from something else we used to do, before we changed aformula. Notice the FOD.OOPER*6 where we doing math on the incoming value


 C*EXEC SQL
 C* SELECT (FOD.OOPER*6) INTO :W7CAL1 FROM FOD WHERE FOD.ODID='OD'
 C* AND FOD.OORD=:W7ORD AND FOD.OOPNO=:W7OPNO
 C*END-EXEC

Defining a cursor can get as complicated as doing CL OPNQRYF

Notice that each row here is actually selected columns from a combinationof files.


 C/EXEC SQL
 C+ DECLARE C1 CURSOR FOR SELECT
 C+ SORD,SQREQ,SOFAC,IPROD,IDESC,IFII,IITYP,ICLAS,OOPNO,OWRKC,OOPDS
 C+ OOL,OOPER,OSTAT,SORTEM,OCDTE
 C+ FROM FSO,IIM,FRT,FOD WHERE SID='SO' AND IID='IM' AND
 C+ RID='RT' AND ODID IN('OD','RD') AND SPROD=IPROD AND SPROD=RPROD
 C+ AND SORD=OORD AND ROPNO=OOPNO AND OSTAT IN('1','3')
 C+ GROUP BY
 C+ SORD,SQREQ,SOFAC,IPROD,IDESC,IFII,IITYP,ICLAS,OOPNO,OWRKC,OOPDS
 C+ OOL,OOPER,OSTAT,SORTEM,OCDTE
 C+ ORDER BY SORD,OOPNO,OSTAT
 C/END-EXEC
  *

Adam Glauser wrote:
> >My question is this: is there a way to determine the number
> >of rows selected?

Al Mac wrote:
> In embedded SQL, and other SQL/400 for that matter, you can get a
>
> COUNT(*) of some record selection
> which tells you HOW MANY records (rows)
> were involved in whatever you were doing.

Al -
Am I correct that you mean I would first do my "SELECT field1, field2"
query, then do a "SELECT COUNT(*)" query with the same WHERE/GROUP BY/
HAVING?  I was hoping there would be some sort of count in the data
structures returned by the DBMS.  Is there significant processing involved
with doing the COUNT(*) query, or does the DBMS somehow cache the results
from the initial SELECT?

Thanks for the tip,
Adam

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