[Dbix-class] Using 'DISTINCT ON' clause in select statement

[Paul Steinkamp]

Greetings,

I'm using postgres as my DB which will accept the clause:

	SELECT DISTINCT ON ( field1, ..., fieldn)    fieldA, fieldB,...  
FROM ....

Note there is no comma after the closing ')' after the 'DISTINCT ON'  
clause. My various attempts either end up not getting it included at  
all or included as a function (and therefore separated from the  
selection field lists by a comma).

Is there a way within the class (short of raw SQL) to perform this  
kind of select?

Thanks,
Paul