how can used DISTINCT for this pivote table

declare @day  int
   set @day = 2

   declare @days varchar(8000)
   set @days = '[1]'
   -- Declare final column names for Pivot 
   Declare @columnsday NVARCHAR(MAX)
  set @columnsday = 'isnull(cast([1] as varchar(10)),'''') as [1]'
   WHILE (@day <= 31)
   BEGIN
       set @days = @days + ', ' + quotename(convert(varchar, @day)) 
       set @columnsday = @columnsday + ',ISNULL(cast(' + quotename(convert(varchar, @day)) + ' as varchar(10)) ,'''') as '+ quotename(convert(varchar, @day))
      set @day  = @day + 1
       --print @days   
   END
   --print @days 
   --print @columnsday

   DECLARE @query varchar(8000)  
   set @query = 'SELECT (StudentCode)as StudentCode,(Stuname) as StudentName,' + @columnsday  + ' from 
     (SELECT tbl_StudentAttendanceDetails.StuAttendId,tbl_StudentAttendanceDetails.StudentCurrId,
     StudentCode,upper(First_Name + '' '' + Middle_Name + '' '' + Last_Name) as Stuname,
     day(StudentAttendanceDate) as day,Stuattend FROM tbl_StudentAttendanceDetails 
     inner join 
     tbl_StudentAttendanceMaster 
     on tbl_StudentAttendanceDetails.StuAttendId=tbl_StudentAttendanceMaster.StuAttendId
   inner join tbl_Student_Current 
   on tbl_StudentAttendanceDetails.StudentCurrId=tbl_Student_Current.StuCurrentId
   inner join StudentAdmission on tbl_Student_Current.StudentId=StudentAdmission.StudentId


         ) AS SourceTable   

      pivot ( 
            MAX(Stuattend)
               for day in (' + @days +')
             )p'

 print('pivoted report')    
--exec(@query)  
EXECUTE  (@query)