Linq - SQL query conversion - sql

Question

Can some one help me to convert this query to linq? I dont know how to use union and then sum in linq.
SELECT Patientname, SUM(A)AS Trec
FROM (SELECT Pm.Patientname, COUNT(*)AS A
FROM Facilitycheckinholdorder Fcho
INNER JOIN Medordertype Mot ON Fcho.Orderseq = Mot.Orderseq
JOIN Patientmaster Pm ON Mot.Patientseq = Pm.Patientseq
AND Fcho.Filleddate BETWEEN '2011-09-01 00:00:00:000' AND '2012-10-16 00:00:00:000'
AND Mot.Facilityid = 139
GROUP BY Pm.Patientname
UNION ALL
SELECT Pm.Patientname, COUNT(*)AS A
FROM Rxqdeliveryholdorder Rdho
INNER JOIN Medordertype Mot ON Rdho.Orderseq = Mot.Orderseq
JOIN Patientmaster Pm ON Mot.Patientseq = Pm.Patientseq
AND Rdho.Filleddate BETWEEN '2011-09-01 00:00:00:000' AND '2012-10-16 00:00:00:000'
AND Mot.Facilityid = 139
GROUP BY Pm.Patientname
) AS Trec
GROUP BY Patientname;

Answer 1

In fact this is not a real question, but I've tried my best...
var lst1 =
from fhco in facilitycheckinholdorder
join mot in meordertype on mot.orderseq equals fhco.orderseq
join pm in patientmaster on mot.patientseq equals pm.patientseq
where
fcho.FilledDate >= new DateTime(2011, 9, 1)
fcho.FilledDate <= new DateTime(2012, 10, 16)
select pm;
var lst2 =
from rdho in rxqdeliveryholdorder
join mot in meordertype on rdho.orderseq equals mot.orderseq
join pm in patientmaster on moit.patientseq equals pm.patientseq
where
fcho.FilledDate >= new DateTime(2011, 9, 1)
fcho.FilledDate <= new DateTime(2012, 10, 16)
select pm;
var res =
from item in lst1.Union(lst2)
select new { Name = item.patientname, Count = lst1.Count() + lst2.Count() };

Answer 2

Key points:
Your outermost query seems redundant.
Your names are not common C# style, and it makes them difficult to read.
UNION ALL corresponds to Concat, not Union.
Getting the Concat out of the way early lets you streamline the query. You could do this in the SQL.
.
var result =
from order in Queryable.Concat(
FacilityCheckInHoldOrder.Select(o => new { o.OrderSeq, o.FilledDate }),
RxqDeliveryHoldOrder .Select(o => new { o.OrderSeq, o.FilledDate }))
where order.FilledDate >= new DateTime(2011, 9, 1) &&
order.FilledDate < new DateTime(2012, 10, 16)
join type in MedOrderType.Where(t => t.FacilityID == 139)
on order.OrderSeq equals type.OrderSeq
join patient in PatientMaster
on type.PatientSeq equals patient.PatientSeq
group by patient.PatientName into grp
select new
{
PatientName = grp.Key,
Trec = grp.Count()
};