2563044 - Error 325 raised by UNION ALL that includes ORDER BY - SAP ASE

• Error 325 is raised  when a SELECT query contains UNION ALL and ORDER BY clause:

Msg 325, Level 18, State 1:
Line 1:
Adaptive Server finds no legal query plan for this statement. If an Abstract Plan is forcing the query plan, check its correspondence to the query. If not, please contact SAP Technical Support.

• The query structure is similar to:

SELECT DISTINCT 
...
FROM
   db1..t1,
   db1..t2
WHERE
...
UNION ALL
SELECT DISTINCT
...
FROM
   db1..t1,
   db1..t2
WHERE
...
GROUP BY
...
ORDER BY
   t2.col2 DESC

• The error does not occur when using:

• UNION ALL but no ORDER BY

• UNION with or without ORDER BY

• SAP Adaptive Server Enterprise (ASE) 15.7 SP139 
• SAP Adaptive Server Enterprise (ASE) 16 SP03

CR811815, CR#811815, 811815 , KBA , BC-SYB-ASE , Sybase ASE Database Platform (non Business Suite) , Bug Filed