How to join 3 tables with lambda expression?

Question

I have a simple LINQ lambda join query but I want to add a 3rd join with a where clause. How do I go about doing that?

Here\'s my single join query:

var         


        

Answer 1

Okay, I can't see why you'd want to select sector_code when you already know it, but I think you want this:

var query = from company in Companies
            join sector in Sectors
              on company.SectorCode equals sector.SectorCode
            join industry in DistributionSectorIndustry
              on sector.SectorCode equals industry.SectorCode
            where industry.Service == "numerical"
            select new {
                company.EquityCusip,
                company.CompanyName,
                company.PrimaryExchange,
                company.SectorCode,
                sector.Description,
                industry.IndustryCode
            };

Notes:

• I've changed it into a query expression as that's a much more readable way of expressing a query like this.
• Although the "where" clause comes after the join, assuming this is a LINQ to SQL or Entity Framework query, it shouldn't make any difference
• I've lengthened the range variable names for clarity
• I've converted your other names into conventional .NET names; you can do this too in your model