where clause subquery in LINQ - sql

Question

I am trying to convert my SQL syntax to the LINQ query , And I have a problem with a subquery.
I want to select max date-time with an Id in a table as a subquery for another select command but I don't know what's right or wrong with this below code.
what I have in Sql
select ap.* ,aph.Lat as 'personLat',aph.Lng as 'personLng',l.cityId,l.Lat as 'LifecenterLat',l.lng as 'LifecenterLng',l.Id as 'LifeCenterId'
from Applicant ap
inner join ApplicantAddressHistory aph on ap.Id = aph.ApplicantId
inner join LifePlusCenter l on aph.CityId = l.CityId
Where ap.FamilyRoleTypeId = '82e26080-fda6-4396-946c-40d0e267f1f3' and aph.CreatedDate in (select max(CreatedDate) from ApplicantAddressHistory
where ApplicantAddressHistory.ApplicantId = ap.Id)
order by ap.NationalityCode
And what I have tried in linq
var innerJoinMultipleTables = from app in db.Applicant.Where(x => x.FamilyRoleTypeId == Guid.Parse("82e26080-fda6-4396-946c-40d0e267f1f3"))
join aph in db.ApplicantAddressHistory on app.Id equals aph.ApplicantId
where aph.CreatedDate == db.ApplicantAddressHistory.Max(x => x.CreatedDate && x.Id=aph.Id)
join l in db.LifePlusCenter on aph.CityId equals l.CityId
let centerLat = l.Lat
let centerLng = l.Lng
orderby app.NationalityCode
select new { app, aph.Lat, aph.Lng, l.CityId, l.Branch, centerLat, centerLng };
without this below line of code ,my linq works correctly.
where aph.CreatedDate == db.ApplicantAddressHistory.Max(x => x.CreatedDate && x.Id=aph.Id)
I need something like this below code in Linq as a subquery
select max(CreatedDate) from ApplicantAddressHistory where ApplicantAddressHistory.ApplicantId = '9836CEC4-EDCB-492C-9899-DF4279210CD2'
I finally tried this and it workd but dont know its correct way or not?!
var innerJoinMultipleTables = from app in db.Applicant.Where(x => x.FamilyRoleTypeId == Guid.Parse("82e26080-fda6-4396-946c-40d0e267f1f3"))
join aph in db.ApplicantAddressHistory on app.Id equals aph.ApplicantId
let rept_max = (from c in db.ApplicantAddressHistory
where c.Id == app.Id
select c.CreatedDate).Max()
where aph.CreatedDate == rept_max
join l in db.LifePlusCenter on aph.CityId equals l.CityId
let centerLat = l.Lat
let centerLng = l.Lng
orderby app.NationalityCode
select new { app, aph.Lat, aph.Lng, l.CityId, l.Branch, centerLat, centerLng };

Answer 1

Am not sure how it works in Linq, but you can modify your query like below to get latest details as per CreatedDate for each ApplicantId.
select ap.* ,aph.Lat as 'personLat',aph.Lng as 'personLng',l.cityId,l.Lat as 'LifecenterLat',l.lng as 'LifecenterLng',l.Id as 'LifeCenterId'
from Applicant ap
inner join
(select *
from
(select *,row_number() over(partition by ApplicantId order by CreatedDate desc) rw
from ApplicantAddressHistory
) p
where p.rw=1
) aph
on ap.Id = aph.ApplicantId
inner join LifePlusCenter l
on aph.CityId = l.CityId
Where ap.FamilyRoleTypeId = '82e26080-fda6-4396-946c-40d0e267f1f3'
/*
and aph.CreatedDate in (
select max(CreatedDate) from ApplicantAddressHistory
where ApplicantAddressHistory.ApplicantId = ap.Id
)
*/
order by ap.NationalityCode

Answer 2

Finally I came up to :
var z = from app in db.Applicant
join aph in db.ApplicantAddressHistory on app.Id equals aph.ApplicantId
join l in db.LifePlusCenter on aph.CityId equals l.CityId
let createDate = app.ApplicantAddressHistory.Max(c => c.CreatedDate)
where createDate.HasValue && aph.CreatedDate == createDate
&& app.FamilyRoleTypeId == Guid.Parse("82e26080-fda6-4396-946c-40d0e267f1f3")
let personLat = aph.Lat
let personLng = aph.Lng
let centerId = l.Id
let LifecenterLat = l.Lat
let LifecenterLng = l.Lng
orderby app.NationalityCode
select new { app, aph, l, app.Id, l.CityId, centerId, personLat, personLng, LifecenterLat, LifecenterLng };