Intro To MDX Decathlon-Hierarchy Navigation Basics (6/10)

Hierarchies are a great asset to cube users. They allow them to drill down into increasing levels of detail with a click. Since hierarchies are so pervasive in cubes, it is pretty much guaranteed that folks who write MDX against cubes will need to perform hierarchy navigation at some point. There are many MDX functions that allow you to move up and down or side to side in hierarchies. Since this is an Intro, we will keep things pretty simple and just describe five basic ones, as shown in Table 1. For each function, I indicate what kind of object that function takes for input (argument) and also what kind of object it outputs (object returned). I do this so that you will know how to nest them properly in order to perform more advance logic. For example, if function A takes in a member and outputs a set and Function B takes in a set, you can pass an expression with Function A as the input to Function B.