-- Define variables to hold the values
VARIABLE old_jqp NUMBER;
VARIABLE new_jqp NUMBER;
VARIABLE sleep_time NUMBER;

-- Store the current value in the variable and set sleep_time and new_jqp
BEGIN
  :sleep_time := 5;
  :new_jqp := 0;
  SELECT TO_NUMBER(value) INTO :old_jqp FROM v$parameter WHERE name = 'job_queue_processes';
END;
/

prompt Current job_queue_processes value:
PRINT old_jqp

prompt Setting job_queue_processes to:
PRINT new_jqp

BEGIN
  -- Set job_queue_processes to 0 using bind variable
  EXECUTE IMMEDIATE 'ALTER SYSTEM SET job_queue_processes='||:new_jqp||' SCOPE=BOTH';
  -- Wait :sleep_time seconds to ensure the change is applied
  DBMS_LOCK.sleep(:sleep_time);
  -- Use the variable to restore the original value using bind variable
  EXECUTE IMMEDIATE 'ALTER SYSTEM SET job_queue_processes='||:old_jqp||' SCOPE=BOTH';
END;
/