Help w/MaxDB Function; also: how does the "Debug SQL" function work?

Question

Hi there forum folks,
In my former life, I was a Basis guy, but I haven't had the pleasure of working directly with SAP applications in a few months.  My current project is to attempt to use MaxDB in a real estate environment.  We're tracking home listings so that we can build statistical reports... such as "what agents are in the Top 100 in postal code X?"
Anyway, as part of this project, I have attempted to construct my very first MaxDB database function.  Unfortunately, it doesn't give me the answers I'm hoping to see.  Here's the function:
CREATE FUNCTION COUNT_LISTINGS (AGENTID CHAR(10)) RETURNS FIXED(6,1) AS
  VAR COLISTINGAGENTID CHAR(10);
      LISTINGAGENTID   CHAR(10);
      MLSNUMBER        CHAR(7);
      UNITS            FIXED(6,1);
  SET UNITS = 0;
  DECLARE FUNCTIONRESULT CURSOR FOR
    SELECT MLSNUMBER,
           LISTINGAGENTID,
           COLISTINGAGENTID FROM FREDDIE.GLAR_SOLDS
     WHERE LISTINGAGENTID = :agentid OR COLISTINGAGENTID = :agentid;
  IF $COUNT IS NULL THEN
    BEGIN
      CLOSE FUNCTIONRESULT;
      RETURN UNITS;
    END
  ELSE
    SET $RC = 0;
  WHILE $RC = 0 DO BEGIN
    FETCH FUNCTIONRESULT INTO :mlsnumber, :listingagentid, :colistingagentid;
    IF ( LISTINGAGENTID   = AGENTID AND COLISTINGAGENTID IS NULL ) OR
       ( COLISTINGAGENTID = AGENTID AND LISTINGAGENTID   IS NULL ) THEN
      SET UNITS = UNITS + 1
    ELSE
      SET UNITS = UNITS + 0.5;
  END;
CLOSE FUNCTIONRESULT;
RETURN UNITS;
I've tried to follow the official MaxDB documentation.  My first deviation from that standard was the use of the "$COUNT" variable (instead of the "$RC" variable) immediately after the DECLARE/SELECT statement above.  When I tried to use $RC, for either a successful or unsuccessful query, $RC was always set to a non-zero value.
I believe I'm past that, but now my issue is down around that FETCH statement.  The UNITS variable doesn't end up with the value I expect.  I know that it can be terribly confusing to try to analyze someone else's logic, but here's a brief narrative that describes what I'm trying to do...
The GLAR_SOLDS table holds one line for each home sold.  It's keyed by the MLSnumber.  Each record also stores up to four agents who've been involved in the transaction: the listing agent, the co-listing agent, the selling agent, and the co-selling agent.  The database function I've written above pertains to the listing side only.  If I can get this to work, a separate function will process the selling side.  If no co-listing agent is involved in a given sell, that agent should get credit for 1 unit sold.  If he/she has help from a co-listing agent, the agent should only get credit for 1/2 unit sold.
Also, does anyone know how the "Debug SQL" functionality is supposed to work within Database Studio?  When I right-mouse click on my function, and follow the path thru "Debug As...", after entering the connection & function arguments, I'm presented with an empty screen.  If you could point me to some documentation somewhere, I'd gratefully read it.
I'm using MaxDB 7.7.06.09 on Windows XP (WIN32) with MaxDB Database Studio 7.7.06.09 (build 009-123-202-944).
Thanks everyone for your help & advice.
~Fred

Answer 1

Fred,
please either provide the full SQL statements for your example or stick with mine.
I'm not going to build it up myself a second time to suit yours now.
>  But now, my issue is how do I store the resultant data in its own table?
So where is the problem?
INSERT INTO <target table> (field 1, field 2, ...)  (<your query>)  UDPATE DUPLICATES-
With my tables this looks like this:
create table sell_result (list_agent varchar(20) primary key, SUM_CREDIT fixed (10,2))
insert
into sell_result (list_agent,sum_credit)
    ( select list_agent, sum (credit) as SUM_CREDIT
      from ( select sh.object_id,lag.name as list_agent, 1 as credit
             from soldhomes sh join agents lag on lag.id = sh.list_agent_id
            union all
             select sh.object_id, lag.name as list_coagent, 0.5 as credit
             from soldhomes sh join agents lag on lag.id = sh.list_coagent_id
      group by list_agent
update duplicates
Check what we have now
sqlcli db770=> select * from sell_result
| LIST_AGENT           | SUM_CREDIT        |
| -------------------- | ----------------- |
| Lars                 |              4.50 |
| Lisa                 |              3.00 |
| Mona                 |              2.50 |
| Paul                 |              2.50 |
4 rows selected (600 usec)
Now add some sales data...
Insert into soldhomes values (11, 1, 2, NULL, NULL)
Insert into soldhomes values (12, 2, NULL, NULL, NULL)
Insert into soldhomes values (13, 2, NULL, NULL, NULL)
Re-run the INSERT command and you're done:
sqlcli db770=> select * from sell_result
| LIST_AGENT           | SUM_CREDIT        |
| -------------------- | ----------------- |
| Lars                 |              5.50 |
| Lisa                 |              3.00 |
| Mona                 |              5.00 |
| Paul                 |              2.50 |
4 rows selected (390 usec)
Neat, isn't it?