Doing 2 Left Joins on the same table with one call - linq

Question

I have the following tables:
Users:
userId, userFirstName, userLastName.
holdBilling:
bEntityID, CarrierOID, PayerOID, holdTYPE, createUserID.
carrier:
carrierOID, carrierName.
payer:
payerOID, payerName.
I want the code to save in a new entity
holdBilling => new
{
FirstName, LastName, CarrierName, PayerName
}
One of these Entities has either a payer or a carrier value (cannot have both). Basically i want to make 2 left joins on the same table with one call. This would be the SQL query that would work for me.
SELECT TOP 1000 [ID]
,[bEntityID]
,c.carrierID
,c.carrierName
,p.payerID
,p.payerName
,[holdType] ( this is "C" for carrier and "P" for payer )
FROM .[dbo].[holdBilling] hb
left join dbo.payer p on hb.payerID = p.payerID
left join dbo.carrier c on hb.carrierID = c.carrierID
where [bEntityID] = 378
The temporary solution I've found is getting a list of all Carriers
var listC = (from hold in holdBilling
join u in Users on hold.createUserID equals u.userID
join c in carrier.DefaultIfEmpty() on hold.carrierID equals c.carrierID
select new
{
Elem = hold,
FName = u.userFirstName,
LName = u.userLastName,
Carrier = c.carrierName,
Payer = ""
}).ToList();
and one for all payers
select new
{
Elem = hold,
FName = u.userFirstName,
LName = u.userLastName,
Carrier = "",
Payer = p.payerName
}).ToList();
and merging the two,I'm confident there has to be a solution for doing both in one query.

Answer 1

Something like this maybe:
var listC = (
from hb in holdBilling
from p in payer.Where(a=>a.payerID==hb.payerID).DefaultIfEmpty()
from c in carrier.Where(a=>a.carrierID=hb.carrierID).DefaultIfEmpty()
where hb.bEntityID==378
select new
{
hb.bEntityID,
c.carrierID,
c.carrierName,
p.payerID,
p.payerName,
holdType=(payer==null?"P":"C")
}
).Take(1000)
.ToList();

Answer 2

You need to use DefaultIfEmpty to do a left join
var listC = (from hold in holdBilling
from u in Users.Where(x => hold.createUserID == x.userID).DefaultIfEmpty()
from c in carrier.Where(x => hold.carrierID == x.carrierID).DefaultIfEmpty()
select new
{
Elem = hold,
FName = u.userFirstName,
LName = u.userLastName,
Carrier = c.carrierName,
Payer = ""
}).ToList();