RE: dynamic SQL in RPG

["Scott Guenther" <scott.guenther@xxxxxxxxxxx>]

James,

It should work if you get sqlstatement formatted correctly for the prepare.
You need to put quotes around any character fields you might have.

In the d specs, define QUOTE as a constant using const(''''), then use it to
build the statement.

Something like:
'VENDORP.VMNAME LIKE ' + QUOTE + '%' + %trim(searchvnd) + '%' + QUOTE

Would evaluate to this for the prepare statement:
VENDORP.VMNAME LIKE '%MYVENDOR%'

-Scott




From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of James Rich
Sent: Wednesday, March 31, 2004 7:16 PM
To: RPG programming on the AS400 / iSeries
Subject: RE: dynamic SQL in RPG


On Wed, 31 Mar 2004, Bob Cozzi wrote:

> Look at the PREPARE and DECLARE SQL statements. They will do what you
want.

That's exactly what I've been looking at.  Everything that I've tried
doesn't work.  I'll post some actual code so maybe someone will point out
where I'm being stupid.

C                   if        (SHVNDNAME = *blanks)
C                   eval      sqlstatement = 'SELECT POHDRP.POCOMP#,' +
C                                     'POHDRP.POLOC#,POHDRP.POPO#,' +
C                                     'POHDRP.POPOSUF,POHDRP.POWO#,' +
C                                     'POHDRP.POPODATE,POHDRP.POSUPNAME '+
C                                     'FROM POHDRP ' +
C                                     'WHERE POHDRP.POPO# >= ' +
C                                     %trim(%editc(SHPO#:'3')) + ' ' +
C                                     'AND POHDRP.POCOMP# IN (' +
C                                     %trim(%editc(co#0:'3')) + ',' +
C                                     %trim(%editc(co#1:'3')) + ',' +
C                                     %trim(%editc(co#2:'3')) + ') ' +
C                                     'ORDER BY POHDRP.POCOMP#,' +
C                                     'POHDRP.POLOC#,POHDRP.POPO#,' +
C                                     'POHDRP.POPOSUF'
C*
C                   else
C                   eval      sqlstatement = 'SELECT POHDRP.POCOMP#,' +
C                                     'POHDRP.POLOC#,POHDRP.POPO#,' +
C                                     'POHDRP.POPOSUF,POHDRP.POWO#,' +
C                                     'POHDRP.POPODATE,VENDORP.VMNAME ' +
C                                     'FROM POHDRP,VENDORP ' +
C                                     'WHERE POHDRP.POPO# >= ' +
C                                     %trim(%editc(SHPO#:'3')) + ' ' +
C                                   'VENDORP.VMVNDRID=POHDRP.POSUPPLIER'+
C                                     ' AND VENDORP.VMNAME LIKE ' +
C                                     searchvnd + ' ' +
C                                     'AND POHDRP.POCOMP# IN (' +
C                                     %trim(%editc(co#0:'3')) + ',' +
C                                     %trim(%editc(co#1:'3')) + ',' +
C                                     %trim(%editc(co#2:'3')) + ') ' +
C                                     'ORDER BY POHDRP.POCOMP#,' +
C                                     'POHDRP.POLOC#,POHDRP.POPO#,' +
C                                     'POHDRP.POPOSUF'
C                   endif
C*
C/EXEC SQL
C+ PREPARE S1 FROM :sqlstatement
C/END-EXEC
C/EXEC SQL
C+ DECLARE C1 CURSOR FOR S1
C/END-EXEC
C/EXEC SQL
C+ OPEN C1
C/END-EXEC

Notice that the difference between the two if conditions is that the first
does use the vendor name and part of the selection criteria and the second
does (as well and joining with another file).  When I run this it does
work.  I tried putting the PREPARE statement inside the if conditionals
and that doesn't work, either.

I don't want to just have variables in the select statement (like using
:variablename for instance) but I want to dynamically change the entire
sql statement.

This is a piece of cake with C and MySQL:

if (condition)
{
        sprintf (query,
        "SELECT custnum,description FROM todolistheader WHERE id = %d",
        job_id);
}
else
{
        sprintf (query,
        "SELECT name, nickname FROM customerlist WHERE id = %d",
        cust_id);
}

mysql_query (&mysql, query);

Can RPG with SQL really be that much harder?  Am I just being stupid?

James Rich

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