hi Ravi,
Thanks for replying,
this issue was resolved, and the solution is the following,
select ROW_NUMBER() over ( ) as "ID",
MONTH_NAME, sum(AMOUNT_SOLD) from _SYS_BIC."efashion/EFASHION_STAR_SCHEMA" where CITY='Austin' and YR = 2001 GROUP BY MONTH_NAME; CITY
Thanks to answer in sap internal community which precised that using ROW_NUMBER() over ( ) is cheaper than using it with a partition.
Thanks & regards
Mohamed Ali