When you visualize data, it is sliced into pieces, which are represented by different types of markers, for example, table cells, bar segments, line vertexes, or pie sectors. When you want to perform calculations that involve various combinations of slices, there are different methods available to reference these combinations. The methods are called node navigation methods, and they are used together with the OVER statement.

The following illustration will serve as a base to clarify the different node navigation methods. It shows a time hierarchy where nodes represent various slices of the data.

The topics below introduce the different node navigation methods. The expressions used assume that in-memory data is used.