COUNT

Returns the number of rows matching the query criteria.

SELECT COUNT(*) FROM Contacts WHERE VID = '123456789'

COUNT(DISTINCT)

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

SELECT COUNT(DISTINCT City) AS DistinctValues FROM Contacts WHERE VID = '123456789'

AVG

Returns the average of the column values.

SELECT Country, AVG(AnnualRevenue) FROM Contacts WHERE VID = '123456789'  GROUP BY Country

MIN

Returns the minimum column value.

SELECT MIN(AnnualRevenue), Country FROM Contacts WHERE VID = '123456789' GROUP BY Country

MAX

Returns the maximum column value.

SELECT Country, MAX(AnnualRevenue) FROM Contacts WHERE VID = '123456789' GROUP BY Country

SUM

Returns the total sum of the column values.

SELECT SUM(AnnualRevenue) FROM Contacts WHERE VID = '123456789'