COUNT

Returns the number of rows matching the query criteria.

SELECT COUNT(*) FROM MyCalendar WHERE Status = 'confirmed'

COUNT(DISTINCT)

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

SELECT COUNT(DISTINCT Id) AS DistinctValues FROM MyCalendar WHERE Status = 'confirmed'

AVG

Returns the average of the column values.

SELECT Description, AVG(AnnualRevenue) FROM MyCalendar WHERE Status = 'confirmed'  GROUP BY Description

MIN

Returns the minimum column value.

SELECT MIN(AnnualRevenue), Description FROM MyCalendar WHERE Status = 'confirmed' GROUP BY Description

MAX

Returns the maximum column value.

SELECT Description, MAX(AnnualRevenue) FROM MyCalendar WHERE Status = 'confirmed' GROUP BY Description

SUM

Returns the total sum of the column values.

SELECT SUM(AnnualRevenue) FROM MyCalendar WHERE Status = 'confirmed'