Which of the following actions can be performed with PROC SQL?

The correct choice is focused on the capabilities of PROC SQL within SAS. This procedure is particularly powerful for database-like operations, allowing users to perform tasks such as aggregating data and joining multiple tables.

Aggregation refers to the ability to summarize data, for example, by calculating sums, averages, or counts for groups of data in a table. Joining tables allows you to combine datasets based on common keys, producing a consolidated view of the data from multiple sources.

While there are various other options listed, they do not accurately represent the primary functions of PROC SQL. For instance, physically rearranging dataset variables is typically done through data step manipulations rather than SQL commands. Additionally, creating datasets without filtering data is within the capabilities of the DATA step in SAS, rather than PROC SQL alone; SQL primarily emphasizes data querying and transformation operations. Lastly, defining new formats for variables is handled through specific SAS format procedures rather than SQL functionalities. Hence, the focus on aggregation and joining of tables makes the second choice distinctly correct regarding what can be accomplished using PROC SQL.