Well part of the update is getting the data. You don't need to update the retrieved Item
var pages = tree.SelectNodes("YourPageType")
.Path("/Products")
.WhereNotNull("NodeSKUID")
.Columns("Column0", "Column1", "Column2");
Or you can select specific SKU info
SKUInfoProvider.GetSKUs().Where(....
You can read more about using Object Query at docs.kentico.com/.../retrieving-database-data-using-objectquery-api