What is the primary use of the GREATEST function in T-SQL?

The GREATEST function in T-SQL is primarily used to determine the highest value from a list of expressions or columns. This function takes multiple arguments and evaluates them to identify which one holds the maximum value. It is particularly useful in scenarios where there are several comparable values, allowing users to easily retrieve the largest one without needing additional logic or nested queries.

This function is commonly applied in data analysis tasks where determining the peak performance, highest sales figures, or maximum measurements is crucial. Its straightforward usage simplifies SQL queries that need to return the highest of several potential values in a single row or across multiple columns.