Question

If I have a sql table that contains

ProductID

Price

Date

and I wish to find the latest price for a given date. In Sql I can do something like

`
Select * from (

select ROW_NUMBER() OVER (PARTITION BY ProductID ORDER BY Date DESC) AS row_number,

ProductID, Date, Price from ProductPrices

where date < @targetDate

) tempTable

where row_number = 1
`

Is it possible to do this easily in LinqToSql? My attempts have all ended up issuing on sql command per product?

Answer 1

How about something like this:

var query = from product in db.Products
            where product.Date < targetDate
            orderby product.Date descending
            group product by product.ProductID into groups
            select groups.First();

It’s possible that calling First won’t work but FirstOrDefault will – someone else found that recently in a similar situation.

EDIT: This solution was driven from the title more than from the SQL (which I don’t fully understand). It aims to find the most recent entry for each product. Hope that’s what you were after!