Question

I have an MSSQL database with LINQ to SQL.
I have three tables.
Requests -> id, string name
Results -> id, requestID, int jumps
Places -> id, resultID, int location

Then, using an input string, I need to get an ICollectable or array or something of Place which meets the following:
Each Request that has name=input, take its ID.[you can assume only one has]
Each Result that has requestID=ID[from above] – take its id.
Each Place that has resultID=‘id[from above]’ – append to array for further processing.

I made it by looping on all Results and then executing another LINQ statement, but its extremely slow [about 500ms for a single request!]. Can I make it any faster?

Thank you!

Edit: Whoops, I also need it grouped by result. aka a List of List of Places, while each inner list contains one column from Result.

Answer 1

You can perform table joins in Linq2Sql using the join keyword:

var places = from request in Requests 
             join result in Results on request.Id equals result.requestID
             join place in Places on result.Id equals place.ResultId
             where request.name = input
             select place;