In the previous exercise, you used the SELECT statement to assign sets to two named axes, ROWS and COLUMNS. The term axes (plural of axis) should be very familiar to you from Chapter 3.
Within that chapter, a cube is described as an n-dimensional space (a cube space), within which the attribute-hierarchies of the cube’s dimensions form axes. The members of the attribute-hierarchies reside at positions along their associated axes. The intersection of members of the various axes within the cube form points identifiable through tuples and cells that contain data reside at those points.
The purpose of the SELECT statement is to define a new cube space. Within this new cube space are axes, such as COLUMNS and ROWS