What is the function of the MERGE statement in SAS?

The MERGE statement in SAS is specifically designed to combine two or more datasets into a single dataset based on common key variables. When using MERGE, the datasets must be sorted by the key variables that are used to align the observations. This statement allows for the combination of datasets in a way that each observation from the participating datasets is matched and merged into one output dataset based on the values of the specified key variables.

This functionality is essential when dealing with relational data, where you may need to consolidate information from different tables that share common identifiers. For instance, if one dataset contains customer details while another contains order details, using the MERGE statement would allow the user to create a comprehensive dataset that includes both customer and order information matched by the customer ID.

Other options do not accurately describe the purpose of the MERGE statement. Splitting datasets or filtering them involves different procedures, such as using the DATA step with conditional statements or PROC SORT to create different datasets. Summarizing data typically involves procedures like PROC SUMMARY or PROC MEANS, which aggregate data rather than combine datasets together.