These are the functions that give you information about the partitioning and addressing. These functions also include Index, First, Last, and Size:

• Index gives an increment as it moves along the addressing within the partition.
• First gives the offset from the first row in the partition; so the first row in each partition is 0.
• Last gives the offset to the last row in the partition; so the last row in each partition is 0.
• Size gives the size of the partition.

The following image shows the various functions:

Index, First, and Last are all affected by scope/partition and direction/addressing, while Size will give the same result at each address of the partition, no matter what direction is specified.