A few things: - Since you're concatenating things together, @CategoryID will have to be converted to a string. Otherwise, SQL Server is trying to perform addition and convert the first variables to an int.
Try changing the SET to this:
SET@FromQuery1 = 'FROM [dbo].[iView_Data_TCG_Aggregated_Product]
WHERE PeriodName = '''+@Time+'''
AND Manufacturer = '''+@Manufacturer+''' AND CategoryId = '''+ cast(@CategoryIDasvarchar(10))
- There was a dangling plus sign I removed from what you posted just to get it to execute - If this is going to be a valid query, your'e missing the SELECT clause with the columns to select.