MVC creating SQL views vs. putting calculations in the controller - sql

Question

I applied for a job, they required me to create a small MVC app before interview which I did. They rejected it saying that I had used bad practices. Please help me figure out what I did wrong!
The task involved a simple database with a Product and a load of Sales (a one to many).
I had to:
display a list of products with total sales
display and allow edition and deletion of the sales
My solution:
create a left joined SQL view which used a group and join to itself to get the sale totals. This table had one row per product
Create an inner joined SQL view with all of the product and sales data. This had one row per sale.
For #1, I just rendered out the view
For #2, I had to render out product details and sales details (a one to many on a single page) so I did the following in the controller:
public ActionResult Details(int id)
{
// get details for the selected product
var product = db.ProductsWithTotals.Where(q => q.ProductId == id).Single();
ViewData["CatalogueNumber"] = product.CatalogueNumber;
ViewData["Title"] = product.Title;
ViewData["Artist"] = product.Artist;
ViewData["TotalSold"] = product.TotalSold;
ViewData["ProductId"] = product.ProductId;
// then pass its sales lines to the view
var salesLines = db.SalesLineDetails.Where(q => q.ProductId == id);
return View(salesLines);
}
If anyone could explain how I could have done this more gracefully, it'd be greatly appreciated.

Answer 1

The only thing I personally would have done differently is:
Use EF (but yeah, L2S is fine for a quickie like this)
Create a ViewModel class for the details View. I use ViewData as sparingly as possible.
But yeah, nothing bad here and I agree that it was probably not a good place to work at. People also tend to make up vague reasons if they didn't want to say they didn't like your face.
/shrug