select TASKID,TASKNAME,CONCAT(TASKID,' - ',TASKDESC) from CCTASK where PROJECT='ZPI2017' 

 order by (CASE 

           WHEN TASKTYPE='JAP' THEN 1

           WHEN TASKTYPE='JAPBEREICH' THEN 2

           WHEN TASKTYPE='JAPVORHABEN' THEN 3

           WHEN TASKTYPE='JAPAP' THEN 4

           WHEN TASKTYPE='TASK' THEN 5

           ELSE 999 END)