null and zero values
There are four types of data that can be saved in a
cube: null values, zero values, non-zero values and strings. A cell that has a
null value is empty. A cell with a zero value contains the figure 0. This is
significant because zero can be used in calculations but null cannot. In no
circumstances are null values and zero values the same thing. A common feature
of multidimensional databases is that they can be “hypersparse”. That is, no
values exist for many combinations of elements. This may happen, for example,
because a product is introduced or discontinued part-way through a year. Both
null and zero values in reports can be suppressed by using filters.