COUNT

Returns the number of rows matching the query criteria.

SELECT COUNT(*) FROM Movies WHERE MovieRating = 'R'

COUNT(DISTINCT)

Returns the number of distinct, non-null field values matching the query criteria.

SELECT COUNT(DISTINCT MovieRuntime) AS DistinctValues FROM Movies WHERE MovieRating = 'R'

AVG

Returns the average of the column values.

SELECT MovieRating, AVG(MovieRuntime) FROM Movies WHERE MovieRating = 'R'  GROUP BY MovieRating

MIN

Returns the minimum column value.

SELECT MIN(MovieRuntime), MovieRating FROM Movies WHERE MovieRating = 'R' GROUP BY MovieRating

MAX

Returns the maximum column value.

SELECT MovieRating, MAX(MovieRuntime) FROM Movies WHERE MovieRating = 'R' GROUP BY MovieRating

SUM

Returns the total sum of the column values.

SELECT SUM(MovieRuntime) FROM Movies WHERE MovieRating = 'R'