I think this would be a nice addition for dialects that do support it. I just stumbled upon a use case where I want to group by a function that takes a parameter, and when the same fragment is reused in the group by clause (the usual workaround) it is not detected as the same fragment and the query will fail. Is there any way we could support this, even though it would be against the spec? Possibily enabled through a config property?