I've got teh same answer ad Ed Wagner does, i just processed your post through a macro so i had some consumable data.

if you want solid help like that int he future, it's up to you to provide consumable data like this to help us generate tested code and answers.

SET DATEFORMAT DMY

;WITH MyCTE([Custmoer NO],[product name], [billed date ])

AS

(

SELECT convert(int,'50'),'Biscuit',convert(date,'1/4/2013') UNION ALL

SELECT '50','Milk','10/4/2013'UNION ALL

SELECT '50','Milk','11/4/2013'UNION ALL

SELECT '50','Curd','15/4/2013'UNION ALL

SELECT '50','Biscuit','14/4/2013'UNION ALL

SELECT '50','Milk','16/4/2013'UNION ALL

SELECT '50','Curd','21/4/2013'UNION ALL

SELECT '50','Biscuit','19/4/2013'UNION ALL

SELECT '50','Curd','26/4/2013'UNION ALL

SELECT '50','Milk','28/4/2013'UNION ALL

SELECT '50','Biscuit','30/4/2013'UNION ALL

SELECT '40','Biscuit','1/4/2013'UNION ALL

SELECT '40','Milk','10/4/2013'UNION ALL

SELECT '40','Milk','11/4/2013'UNION ALL

SELECT '40','Curd','15/4/2013'UNION ALL

SELECT '40','Biscuit','14/4/2013'UNION ALL

SELECT '40','Milk','6/4/2013'UNION ALL

SELECT '40','Curd','21/4/2013'

)

SELECT [Custmoer NO],[product name],COUNT(*)

FROM MyCTE

GROUP BY [Custmoer NO],[product name]

order by [Custmoer NO] DESC,[product name];