Uso de DISTINCT para obtener valores únicos de un historial de pagos a empleados. [OrtizOL]

ValoresUnicos.sql

SELECT RateChangeDate, 
    COUNT(Rate) AS 'Contador', 
    COUNT(DISTINCT Rate) AS 'Valores Distintos' 
    FROM HumanResources.EmployeePayHistory
    WHERE RateChangeDate >= '2003-01-01T00:00:00.000' 
        AND RateChangeDate < '2003-01-10T00:00:00.000'
    GROUP BY RateChangeDate;