How do you concatenate datasets in SAS?

When concatenating datasets in SAS, using the SET statement in a DATA step is the standard approach. The SET statement allows you to stack datasets on top of each other, effectively creating one continuous dataset that combines all the observations from the specified datasets.

For instance, if you have two datasets named dataset1 and dataset2, using a statement like DATA combined; SET dataset1 dataset2; RUN; will create a new dataset called combined that includes all observations from both dataset1 and dataset2. This is a straightforward and commonly used method for concatenation in SAS, making it an essential technique for data manipulation.

While other methods like the MERGE statement can combine datasets based on matching key variables, this is not true concatenation, as it aligns observations based on those keys instead of simply stacking them. The SQL UNION command is also not used for direct concatenation within a DATA step and typically applies in SQL context, which requires different syntax. Similarly, PROC APPEND is a procedure designed to add new observations from one dataset to an existing dataset, but use of SET is the more fundamental method for concatenation that allows for inline data processing and is thus the correct choice for the question posed.