Yes, the "roll-up" understanding is correct. Defining one hierarchy made up of the three dimensions is good enough. It covers all 3 roll-ups. The order of dimensions matters because hierarchy basically describes a "contains" relationship, like CONTINENT => COUNTRY => CITY. A wrong order will impact performance at both build time and query time.
On Thu, Sep 17, 2015 at 11:27 PM, Patrick McAnneny < [email protected]> wrote: > The way I understand the hierarchy feature (lets say with three columns > specified) is the following: "create a roll-up aggregate grouping by this > column, then that column, then that column" Is this correct understanding? > > If I would want to query potentially based on any combination of those > three roll-ups, would it be best to create three separate hierarchy > dimensions or the combination of each? Would order even matter here? Order > does not usually matter in 'group by' statements >
