COUNT

Returns the number of rows matching the query criteria.

SELECT COUNT(*) FROM Timesheets WHERE JobCodeType = 'regular'

COUNT(DISTINCT)

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

SELECT COUNT(DISTINCT Id) AS DistinctValues FROM Timesheets WHERE JobCodeType = 'regular'

AVG

Returns the average of the column values.

SELECT JobcodeId, AVG(AnnualRevenue) FROM Timesheets WHERE JobCodeType = 'regular'  GROUP BY JobcodeId

MIN

Returns the minimum column value.

SELECT MIN(AnnualRevenue), JobcodeId FROM Timesheets WHERE JobCodeType = 'regular' GROUP BY JobcodeId

MAX

Returns the maximum column value.

SELECT JobcodeId, MAX(AnnualRevenue) FROM Timesheets WHERE JobCodeType = 'regular' GROUP BY JobcodeId

SUM

Returns the total sum of the column values.

SELECT SUM(AnnualRevenue) FROM Timesheets WHERE JobCodeType = 'regular'