SQL Server - Function Error for SELECT - RETURN Value

Hi ....

Here is a Function I want to build in order to return me one value which is a DateTime format ...

I got this error any Time I tried to execute it :

Msg 444, Level 16, State 3, Procedure DateInterval, Line 20
Select statements included within a function cannot return data to a client

I will make a Stored Procedure as a last alternative, but I would like to know if this is related to the fact that I am using a SELECT to get my Return Value ? Make no sense for me

Any help


ALTER FUNCTION [dbo].[DateInterval] (@Month Int, @Year Int, @Interval Int)

RETURNS DateTime  

AS

BEGIN

      DECLARE @MyDate DateTime
      DECLARE @EOMonthDate Datetime
      DECLARE @DateInterval Datetime

      -- Get a date from the two Inputs @Month & @Year
      SET @MyDate = CONVERT(DateTime, CONVERT(VARCHAR(4), @Year) + RIGHT('0' + CONVERT(VARCHAR(2), @Month), 2) + '01', 102)
      SELECT CONVERT(VARCHAR(10),@MyDate ,105)

      -- Get the latest Day-Month from the built Date
      SET @EOMonthDate = (SELECT DATEADD(DAY, -1, DATEADD(MONTH, DATEDIFF(MONTH, 0, @MyDate) +1, 0)))

      -- Return the Date after calculation  
      SET @DateInterval = (SELECT DATEADD(MM, @Interval, @EOMonthDate ))

      -- Return the result of the function
      RETURN @DateInterval
      
END