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c# - inner join in linq to entities

I have entity called Customer and it has three properties:

public class Customer {
    public virtual Guid CompanyId;
    public virtual long Id;
    public virtual string Name;
}

I have also entity called Splitting and it has three properties:

public class Splitting {
    public virtual long CustomerId;
    public virtual long Id;
    public virtual string Name;
}

Now I need to write a method that gets companyId and customerId. The method should return list of splitting that relates to the specific customerId in the companyId. Something like this:

public IList<Splitting> get(Guid companyId, long customrId) {    
    var res=from s in Splitting 
            from c in Customer 
            ...... how to continue?

    return res.ToList();
}
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var res = from s in Splitting 
          join c in Customer on s.CustomerId equals c.Id
         where c.Id == customrId
            && c.CompanyId == companyId
        select s;

Using Extension methods:

var res = Splitting.Join(Customer,
                 s => s.CustomerId,
                 c => c.Id,
                 (s, c) => new { s, c })
           .Where(sc => sc.c.Id == userId && sc.c.CompanyId == companId)
           .Select(sc => sc.s);

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