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

The WHERE statement in PROC SQL is primarily utilized to filter rows based on specific conditions. This functionality allows the user to specify criteria that determine which records are included in the result set of the SQL query. By using the WHERE clause, you can narrow down the data to only those rows that meet your specified conditions. For example, if you're interested in retrieving records of employees with a salary greater than a specific amount, the WHERE clause would enable you to extract only those relevant entries from the dataset.

In contrast, the other provided options serve different purposes. Defining new variables based on conditions is typically handled through the CASE statement or other data manipulation techniques, rather than the WHERE statement. Formatting output results is generally achieved using the FORMAT statement or attributes in SQL, rather than filtering directly. Creating indexes for a dataset involves methods that are focused on improving query performance but is not related to the WHERE statement's functionality.