Converting Oracle SQL query with left outer join to Linq - linq

Question

I'm trying to convert the Oracle Sql query below to linq, without much success. I'm not sure how to handle the line AND ShipSeq = i.ShipSeq(+), which I've learned is a LEFT OUTER JOIN in Oracle. I'm testing the Linq query below in LinqPad, where I don't get any syntax errors but it errors on executing the query. Any ideas?
Oracle Sql Query
SELECT *
FROM CustomerShip,
(SELECT DISTINCT b.ShipSeq AS shipSeq
FROM Orders a,
CustomerShip b
WHERE a.OrderId IN (SELECT OrderId
FROM Orders
WHERE CustomerId = #CustomerId
AND OrderType <> 'A')
AND b.CustomerId = #CustomerId
AND b.ShipSeq = a.CustShip
AND OrderStatus <> 'C'
GROUP BY b.ShipSeq) i
WHERE CustomerId = #CustomerId
AND (Address NOT LIKE '%RETAIL%STORE%')
AND ShipSeq = i.ShipSeq(+)
ORDER BY ShipTo DESC, OrderDate DESC;
Linq Query
var query = from s in CustomerShip
join m in Orders on s.ShipTo equals m.ShipTo into temp
from x in temp.DefaultIfEmpty()
where (from o in Orders
from c in CustomerShip
where (from x in CustomerOrders
where x.CustomerId == customerId
&& !x.OrderType.Equals("A")
select x.OrderId).Contains(o.OrderId)
&& c.CustomerId == customerId
&& c.ShipTo == o.ShipTo
&& !o.OrderStatus.Equals("C")
select c.ShipTo).Distinct().Contains(s.ShipTo)
&& s.CustomerId == customerId
&& !s.Address.Contains("RETAIL")
&& !s.Address.Contains("STORE")
orderby s.ShipTo descending, s.OrderDate descending
select s;

Answer 1

I think a literal translation looks like this:
var iQuerySub = from o in Orders where o.CustomerId == pCustomerId && o.OrderType != "A" select o.OrderId;
var iQuery = (from a in Orders
from b in CustomerShip
where iQuerySub.Contains(a.OrderId) &&
b.CustomerId == pCustomerId &&
b.ShipSeq == a.CustShip &&
a.OrderStatus != "C"
group b by b.ShipSeq into bg
select new { shipSeq = bg.Key }).Distinct();
var ans = from s in CustomerShip
where s.CustomerId == pCustomerId &&
(!s.Address.Contains("RETAIL") || !s.Address.Contains("STORE") || s.Address.IndexOf("RETAIL") > s.Address.IndexOf("STORE"))
join i in iQuery on s.ShipSeq equals i.shipSeq into ij
from i in ij.DefaultIfEmpty()
orderby s.ShipTo, s.OrderDate descending
select new { s, shipSeq = (i != null ? i.shipSeq : (int?)null) };
But both the SQL and LINQ seem inefficient to me, but without domain knowledge this is all I could optimize:
var iQuery2 = (from b in CustomerShip
where b.CustomerId == pCustomerId &&
Orders.Any(a => a.CustomerId == pCustomerId && a.OrderType != "A" && a.OrderStatus != "C" && b.ShipSeq == a.CustShip)
select new { shipSeq = b.ShipSeq }).Distinct();
var ans2 = from s in CustomerShip
where s.CustomerId == pCustomerId &&
(!s.Address.Contains("RETAIL") || !s.Address.Contains("STORE") || s.Address.IndexOf("RETAIL") > s.Address.IndexOf("STORE"))
join i in iQuery2 on s.ShipSeq equals i.shipSeq into ij
from i in ij.DefaultIfEmpty()
orderby s.ShipTo, s.OrderDate descending
select new { s, shipSeq = (i != null ? i.shipSeq : (int?)null) };