Retrive and update existing record from database

Question

Hi, I am using MS SQL Server 2008 to create a stored procedure that is responsible for retrieving and updating existing record from database. However, it does not update the records. I am not sure of what is wrong with the stored procedure.
This is the stored procedure that I have input:

 

ALTER PROCEDURE [OS].[UPDATE_ItemsRecords] 

@itemID varchar(10),

@itemName  varchar(1000),

@itemDesc varchar(10)



AS

Select @itemName = itemName, @itemDesc 
= itemDesc from OS.Items 
WHERE itemID = @itemID 

UPDATE 
OS.Items SET itemName = @itemName , itemDesc = @itemDesc WHERE itemID = 
@itemID 

I am unable to retrive and update the existing records. How do I resolve it?Thks!