I have dwelling on this for hours and still cannot find out how to do this. How do you get the total sales of an item for every year.

What I have got so far is this:

```
SQLCommand.CommandText = @"SELECT SUM SalesNo AS TotalYearSales FROM SalesTable WHERE Product = " + ddItems.SelectedItem + "";.

```

The table headings are as follows Product, Year, SalesNo.