COUNT

Returns the number of rows matching the query criteria.

SELECT COUNT(*) FROM Lead WHERE FirstName = 'Bartholomew'

COUNT(DISTINCT)

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

SELECT COUNT(DISTINCT Id) AS DistinctValues FROM Lead WHERE FirstName <> 'Bartholomew'

AVG

Returns the average of the column values.

SELECT FullName, AVG(AnnualRevenue) FROM Lead WHERE FirstName <> 'Bartholomew'  GROUP BY FullName

MIN

Returns the minimum column value.

SELECT MIN(AnnualRevenue), FullName FROM Lead WHERE FirstName <> 'Bartholomew' GROUP BY FullName

MAX

Returns the maximum column value.

SELECT FullName, MAX(AnnualRevenue) FROM Lead WHERE FirstName <> 'Bartholomew' GROUP BY FullName

SUM

Returns the total sum of the column values.

SELECT SUM(AnnualRevenue) FROM Lead WHERE FirstName = 'Bartholomew'