Hi, please note the test cases below - it should be self-explanatory i am on MonetDB v11.15.7 (Feb2013-SP2), i run the test before the upgrade with the same results please advice thanks a lot milan *test case 1, no ORDER BY - correct** **----------------------------------* WITH SAWITH0 AS ( select 'a' as c1, 'b' as c2, 'c' as c3, 1 as c4 ) select 0 as c1, D1.c1 as c2, D1.c2 as c3, D1.c3 as c4, D1.c4 as c5 from SAWITH0 D1 +------+------+------+------+------+ | c1 | c2 | c3 | c4 | c5 | +======+======+======+======+======+ | 0 | a | b | c | 1 | +------+------+------+------+------+ *test case 2, add ORDER BY - wrong result (repeats the 1st value for all columns)* *--------------------------------------------------------------------------------* WITH SAWITH0 AS ( select 'a' as c1, 'b' as c2, 'c' as c3, 1 as c4 ) select 0 as c1, D1.c1 as c2, D1.c2 as c3, D1.c3 as c4, D1.c4 as c5 from SAWITH0 D1 order by 5, 4, 3, 2 --order by c5,c4,c3,c2 +------+------+------+------+------+ | c1 | c2 | c3 | c4 | c5 | +======+======+======+======+======+ | 0 | a | a | a | a | +------+------+------+------+------+ Note that the result is the same even if you use the column alias instead of the ord.num. * **test case 3, use completely different alias with order by - correct ** **-------------------------------------------------------------------* WITH SAWITH0 AS ( select 'a' as c1, 'b' as c2, 'c' as c3, 1 as c4 ) select 0 as c1, D1.c1 as a2, D1.c2 as a3, D1.c3 as a4, D1.c4 as a5 from SAWITH0 D1 order by 5, 4, 3, 2 +------+------+------+------+------+ | c1 | a2 | a3 | a4 | a5 | +======+======+======+======+======+ | 0 | a | b | c | 1 | +------+------+------+------+------+