COUNT

Returns the number of rows matching the query criteria.

SELECT COUNT(*) FROM Customers WHERE GivenName = 'Cook, Brian'

COUNT(DISTINCT)

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

SELECT COUNT(DISTINCT Id) AS DistinctValues FROM Customers WHERE GivenName = 'Cook, Brian'

AVG

Returns the average of the column values.

SELECT GivenName, AVG(AnnualRevenue) FROM Customers WHERE GivenName = 'Cook, Brian'  GROUP BY GivenName

MIN

Returns the minimum column value.

SELECT MIN(AnnualRevenue), GivenName FROM Customers WHERE GivenName = 'Cook, Brian' GROUP BY GivenName

MAX

Returns the maximum column value.

SELECT GivenName, MAX(AnnualRevenue) FROM Customers WHERE GivenName = 'Cook, Brian' GROUP BY GivenName

SUM

Returns the total sum of the column values.

SELECT SUM(AnnualRevenue) FROM Customers WHERE GivenName = 'Cook, Brian'