Please check http://www.alibaba.com/catalogs/cid/702/Laptops.html they have nice filter here with number of items for each. Note one detail - they have locations here. Same thing on olx.com - location and number of items for each category.
Now imagine I have tables: [products] (Id, Name, CategoryId, LocationId) [Categories] (Id,Name) [Location] (Id, Name)
My question how can I do the same, cause count things even with caching looks expensive? And they give results pretty fast...
Please advice with possible ways to do that in ASP.NET, C#, MVC, MS SQL, but avoice simple answers like "count and change" Thank you in advance.