SQL Table and column Parser for stored procedures

[...]
@MyDate datetime

AS

    IF (day(@MyDate) = 1)
    BEGIN
        SELECT * FROM MyFirstTable
        RETURN
    END

    IF (@MyDate > getdate())
        SELECT MyID, MyText FROM MySecondTable WHERE ADate > @MyDate
    ELSE
        EXEC Other_StoredProcedure @MyType, @MyDate