Explanation: An aggregate function performs a calculation on a set of values, and returns a single value. The following are aggregate functions: * APPROX_COUNT_DISTINCT * AVG * CHECKSUM_AGG * COUNT * COUNT_BIG * GROUPING * GROUPING_ID * MAX * MIN * STDEV * STDEVP * STRING_AGG * SUM * VAR * VARP Reference: https://docs.microsoft.com/en-us/sql/t-sql/functions/aggregate-functions-transact-sql?view=sql-server-ver15