What is the purpose of the WHERE statement in PROC SQL?

The purpose of the WHERE statement in PROC SQL is to filter rows based on specified conditions. When using a WHERE clause, you can specify criteria that must be met for the rows to be included in the results of your query. This allows for targeted data retrieval, helping to refine the dataset to only those observations that are relevant to the specific analysis or report.

By applying conditions in the WHERE statement, users can focus on specific values, ranges, or attributes of the data, thus making data analysis more effective. For instance, if you are working with a dataset of employee records and only want to retrieve those who work in a particular department or have salaries above a certain threshold, using a WHERE statement would allow you to achieve that.

In contrast, the other options illustrate different functions that do not align with the primary role of the WHERE statement. Joining multiple datasets pertains to combining data from different sources, sorting the results involves organizing the data in a certain order, and summarizing data typically pertains to aggregating values. Each of these activities can be performed in PROC SQL, but they utilize other statements or procedures rather than the WHERE statement.