SELECT ACTIVITY_TYPE_ID
, CASE ACTIVITY_TYPE_ID WHEN 1 THEN ACTIVITY_DATE WHEN 2 THEN
DIV_PAY_DATE
ELSE ACTIVITY_DATE
END
AS MAKEDATE
FROM ACTIVITY
WHERE CASE ACTIVITY_TYPE_ID WHEN 1
THEN ACTIVITY_DATE WHEN 2 THEN DIV_PAY_DATE ELSE ACTIVITY_DATE END > '2009-01-01'
ORDER BY ACTIVITY_TYPE_ID, MAKEDATE