Hi, I am working with Mehmet on Monetdb / Mondrian tests. So, to sum up: 1) functions in group by are not supported in ansi sql standard (I take your words on this :-) 2) on the contrary, column aliases in group by are not supported by some major rdbms, eg. Oracle and MS Sqlserver (while functions in group by are) 3) some rdbms support both (eg. Postgresql) 4) Mondrian, as a ROLAP tool, generate sql queries and make great use of aggregates. Those queries contain functions in group by (not standard, but works on Oracle, Sqlserver, Postgres, etc.) So if I understand you, supporting functions in group by in Monetdb would not be a trivial task... Do you confirm we should not count on it (unless we propose a patch, I guess) ? This might well be a showstopper for Mondrian / Monet. A solution might be to change the Mondrian query generator specifically for Monetdb (using a special dialect setting), but it might not be that trivial either (sql generation is widespreaded in mondrian code :-(. Does this sum up the situation ? Franck