What is the functionality of the BY statement in PROC SORT?

The functionality of the BY statement in PROC SORT is to define how the data is grouped for sorting. When you specify one or more variables in the BY statement, PROC SORT organizes the dataset based on the values of those variables. This means that the dataset will be sorted in ascending order based on the specified BY variables.

For instance, if you have a dataset containing information about employees and you want to sort this dataset by department and then by employee name, the BY statement would enable you to achieve this hierarchical sorting. This is especially useful in preparing data for further analysis or reporting, as it helps to logically order the observations according to the specified criteria.

In contrast, the other options discuss functionalities that are not associated with the BY statement in PROC SORT. Specifying variables to include in the output, filtering observations, or renaming the sorted dataset are tasks handled by different statements or procedures within SAS, and therefore, do not apply in the context of the BY statement within PROC SORT.