I have some spl which looks like the following:

...

          DECLARE QCTLSBSD VARCHAR(10);

...

SET QCTLSBSD = null;

...

I am trying the create procedure in Run SQL Scripts.  I've debugged the earlier errors and now I'm down to just this one.  On the earlier ones Run SQL Scripts flagged right where the error was occuring.  On this one I have to find some QSYSPRT on the i and see

...

          CASE QCTLSBSD
            WHEN NULL THEN

...

Record  *...+... 1
  512    = NULL ; 

MSG ID  SEV  RECORD  TEXT                                           
SQL0128  30     512  Position 4 Use of NULL or UNKNOWN is not valid.

If I try changing 

SET QCTLSBSD = null;

to

SET QCTLSBSD is null;

Then Run SQL Scripts stops it with

Message: [SQL0199] Keyword IS not expected. Valid tokens: =.

------------------------------
Robert Berendt IBMChampion
Business Systems Analyst, Lead
Dekko
Fort Wayne
260-599-3160
------------------------------

#SQL

Turns out it WASN'T the SET line.  I commented that out and continued to get the error.

I had another section of code which was

          CASE QCTLSBSD
            WHEN NULL THEN
              SET JOB_COUNT = JOB_COUNT; -- SQL failed, dummy operation.  Replace if desired.
            WHEN 'QCTL' THEN -- Batch subsystem is normally QBATCH
              SELECT COUNT(*) INTO JOB_COUNT
              FROM QSYS2.SUBSYSTEM_INFO
              WHERE SUBSYSTEM_DESCRIPTION = 'QBATCH'
                AND STATUS = 'ACTIVE';
              IF JOB_COUNT = 0 THEN
                CALL QSYS2.QCMDEXC('STRSBS QBATCH');
              END IF;
            WHEN 'QBASE' THEN -- Batch subsystem is just part of QBASE
              -- What to do?  Ensure that QBASE is not 'RESTRICTED'?
              SET JOB_COUNT = JOB_COUNT; -- dummy operation.  Replace if desired
            ELSE  -- This choice location for rent
              SET JOB_COUNT = JOB_COUNT; -- dummy operation.  Replace if desired.
          END CASE;

I changed it to

          CASE 
            WHEN QCTLSBSD IS NULL THEN
              SET JOB_COUNT = JOB_COUNT; -- SQL failed, dummy operation.  Replace if desired.
            WHEN QCTLSBSD = 'QCTL' THEN -- Batch subsystem is normally QBATCH
              SELECT COUNT(*) INTO JOB_COUNT
              FROM QSYS2.SUBSYSTEM_INFO
              WHERE SUBSYSTEM_DESCRIPTION = 'QBATCH'
                AND STATUS = 'ACTIVE';
              IF JOB_COUNT = 0 THEN
                CALL QSYS2.QCMDEXC('STRSBS QBATCH');
              END IF;
            WHEN QCTLSBSD = 'QBASE' THEN -- Batch subsystem is just part of QBASE
              -- What to do?  Ensure that QBASE is not 'RESTRICTED'?
              SET JOB_COUNT = JOB_COUNT; -- dummy operation.  Replace if desired
            ELSE  -- This choice location for rent
              SET JOB_COUNT = JOB_COUNT; -- dummy operation.  Replace if desired.
          END CASE;

1 - I've ran into issues before when trying the previous CASE format.

2 - I read that WHEN NULL acts differently than WHEN IS NULL.  The former continues to do the rest of the WHENs.  The latter does not.  https://sqlundercover.com/2018/11/28/a-curious-case-of-case-when-and-null-values/

------------------------------
Robert Berendt IBMChampion
Business Systems Analyst, Lead
Dekko
Fort Wayne
260-599-3160
------------------------------