SQL Summing daily totals

This example illustrates how to sum values collected daily into monthly categories.

SELECT DISTINCT
CONVERT(varchar(4), YEAR(Date)) + '-' + RIGHT('00' + CAST(DATEPART(mm, Date) AS varchar(2)), 2) AS PERIOD,
  SUM(Steps) AS TotalSteps,
  SUM(Floors) AS TotalFloors,
  SUM(Distance_mi) AS TotalMiles,
  SUM(Activity) AS ActiveMinutes,
 SUM(Calories) AS TotalCalories
 FROM  dbo.FitBit
 GROUP BY CONVERT(varchar(4), YEAR(Date)) + '-' + RIGHT('00' + CAST(DATEPART(mm, Date) AS varchar(2)), 2)