Ugly one:
Even in LINQ you still can run sql queries. Example
IEnumerable<Customer> results = db.ExecuteQuery<Customer>
(@"SELECT c1.custid as CustomerID, c2.custName as ContactName
FROM customer1 as c1, customer2 as c2
WHERE c1.custid = c2.custid"
);
Good one:
Model your schema in designer, and you should not experience problems with righting.
Code will be smth like
var query = from cl in Client
join clad in ClientAddress on cl.id equals clad.clientguid
where cl.clientid='650450' && clad.Address2.StartsWith('150')
select new { l.clientid,clad.address1,clad.address2 }
;