Aggregate functions
SUM(): Adds up numeric values.
AVG(): Calculates the average of numeric values.
MIN(): Retrieves the minimum value from a dataset.
MAX(): Retrieves the maximum value from a dataset.
COUNT(): Counts the number of rows or non-null values.
COUNTD(): Counts distinct values.
MEDIAN(): Finds the middle value in a sorted dataset.
STDEV(): Computes the standard deviation of numeric values.