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How to get the count of values in table using linq

im required to make a query to db to fetch data fro a highchart widget in our site here is the code I use currently,
var highChartsData =
(from a in db.roomdetails
join b in db.ApplySchedule on a.RoomId equals b.RoomID
where b.Status == true
select new HighlinePie
{
Title = a.RoomName,
Date = b.MDate,
Value = db.ApplySchedule.Where(x => x.RoomID == a.RoomId).GroupBy(x=>x.MDate).Count(),
}).ToList();
The problem with this approach is right now get the total count but what i need is the count based on date, for example if there was two entry on date 12/09/20201 and three entry on 14/09/20201 the data should be "Title,12/09/20201,2","Title,14/09/20201,3".

You have to use grouping:
var groupQuery =
from a in db.roomdetails
join b in db.ApplySchedule on a.RoomId equals b.RoomID
where b.Status == true
group b by new { a.RoomName, b.MDate } into g
select new HighlinePie
{
Title = g.Key.RoomName,
Date = g.Key.MDate,
Value = g.Count()
};
var highChartsData = groupQuery.ToList();

How to rewrite sql query to linq

I'm trying to rewrite sql query to linq but can't do it myself.
The most problem for me is to get I,II and III aggregated values.
Sql query:
select o.Name,t.TypeID, SUM(e.I),SUM(e.II),SUM(e.III) from Expenditure e
join Finance f on f.FinanceId = e.FinanceId
join FinanceYear fy on fy.FinanceYearId = f.FinanceYearId and fy.StatusId = 1
join Project p on p.ProjectId = fy.ProjectId
join Organization o on o.OrganizationId = p.OrganizationId
join Type t on t.TypeID = p.TypeID
where fy.Year = 2018
group by o.Name,s.TypeID
and what I have done so far is:
var x = (from e in _db.Expenditures
join f in _db.Finances on e.FinanceId equals f.FinanceId
join fy in _db.FinanceYears on f.FinanceYearId equals fy.FinanceYearId and fy.StatusId = 1 // this does not work, cant join on multiple conditions?
join p in _db.Projects on fy.ProjectId equals p.ProjectId
join o in _db.Organizations on p.OrganizationId equals o.OrganizationId
join s in _db.Types on p.TypeId equals s.TypeId
group new { o, s } by new { o.OrganizationId, s.TypeId }
into grp
select new AggModel
{
OrganizationId = grp.Key.OrganizationId,
TypeId = grp.Key.TypeId,
I = ?,
II = ?,
III = ?,
}
);

Try something like this:
group new { e, o, s } by new { o.OrganizationId, s.TypeId }
into grp
select new AggModel
{
OrganizationId = grp.Key.OrganizationId,
TypeId = grp.Key.TypeId,
I = grp.Sum(a => a.e.I),
II = grp.Sum(a => a.e.II),
III = grp.Sum(a => a.e.III),
}
You'll need to adjust the right side of the lambda to navigate to the correct property.

You Need to use the Group by for aggregation methods.
Check the below link for more Knowledge.
How to use aggregate functions in linq with joins?

Incorrect values after SQL to LINQ convertion

I need to convert following SQL into LINQ
select
app.id,
app.name,
app.version,
s.application,
s.analysis,
s.behaviour,
(select count(ia.id)
from appInstalled ia
JOIN deviceUser ud ON ia.device_id = ud.device_id
where ia.app_id = app.id) as deviceCount,
max(alrt.alert_date)
from application app
left join score s on app.app_md5 = s.md5hash
left join alert alrt on app.id = alrt.app_id
where app.name like '%gpsnav%'
group by device;
This is what I've done so far
var appQuery = (from app in entities.applications
join score in entities.scores on app.app_md5 equals score.md5hash into appScore
join alrt in entities.alerts on app.id equals alrt.app_id into appAlerts
from s in appScore.DefaultIfEmpty()
from a in appAlerts.DefaultIfEmpty()
let deviceCount = (from iapp in entities.appInstalled
join ud in entities.deviceUser on iapp.device_id equals ud.device_id
where iapp.id == app.id
select iapp.id).Count()
where string.IsNullOrEmpty(searchTerm) || app.name.ToLower().Contains(searchTerm.ToLower())
select new
{
AppId = app.id,
AppName = app.name,
AppVersion = app.version,
AppScore = s.application,
Analysis = s.analysis,
Behavior = s.behaviour,
Devices = deviceCount,
AlertDate = a.alert_date
});
var grouped = from a in appQuery
group a by new
{
a.AppId,
a.AppName,
a.AppVersion,
a.AppScore,
a.Analysis,
a.Behavior,
a.Devices,
a.AlertDate
} into g
select new
{
g.Key.AppId,
g.Key.AppName,
g.Key.AppVersion,
g.Key.AppScore,
g.Key.Analysis,
g.Key.Behavior,
g.Key.Devices,
AlertDate = g.Max(x=>x.AlertDate)
};
The above LINQ works but the data is incorrect for Device and AlertDate. What I am missing in here? Also I am not getting max of AlertDate while grouping in LINQ.

linq to sql distinct values or group by

I have the folowing linq query.
How can I modify the query to return distinct values for CityFoo property only?
var query = from f in db.Foos
join b in db.Bars on f.IDFoo equals b.IDFoo
join fb in db.Fubars on b.IDBar equals fb.IDBar
select new MyViewModel {
IDFoo = f.IDFoo,
NameFoo = f.NameFoo,
CityFoo = f.CityFoo,
NameBar = b.NameBar,
NameFubar = fb.NameFubar };

I think you are missing information on your query.
If you want the first value to be used on the other properties, you need to tell that to Linq
So I am guessing that you actually want to group and then take the first.
Or...something like this:
var query = from f in db.Foos
join b in db.Bars on f.IDFoo equals b.IDFoo
join fb in db.Fubars on b.IDBar equals fb.IDBar
group new { f, b, fb } by f.CityFoo into grp
let first = grp.FirstOrDefault()
select new MyViewModel {
IDFoo = first.f.IDFoo,
NameFoo = first.f.NameFoo,
CityFoo = grp.Key,
NameBar = first.b.NameBar,
NameFubar = first.fb.NameFubar };

SQL to Linq select multiple columns in group by

I would like to convert a SQL statement to LINQ but i have some problems doing it.
The sql statement is :
SELECT
C.[Call_Date], CC.[Company], R.Resolution,
COUNT_BIG(*) AS CNT,
SUM([Duration]) AS Total
FROM
[Calls] C
Join
[CompanyCharges] CC on [Company_Charge] = [CompanyCharge]
Join
[Resolutions] R on C.Call_Resolution = R.Resolution
where
Call_Date >= '05/29/2013'
Group By
C.[Call_Date], CC.[Company], CC.[CompanyCharge], R.Resolution, R.Resolution_Order
I wrote something like :
var stats = from c in dbContext.Calls
join cc in dbContext.CompanyCharges on c.Company_Charge equals cc.CompanyCharge
join r in dbContext.Resolutions on c.Call_Resolution equals r.Resolution
where (c.Call_Date > "05/29/2013")
group new { c, cc, r } by new { c.Call_Date, cc.CompanyCharge, r.Resolution, r.Resolution_Order } into statsGroup
select new { Count = statsGroup.Count(), ??? };
I managed to count the elements, but i need a sum[duration] and some columns from different tables.
Please share your wisdome with me.

Assuming that the [Duration] field is part of the [Calls] table:
var stats = /* ... */
select new
{
Count = statsGroup.Count(),
Total = statsGroup.Sum(stat => stat.c.Duration),
};
You'd probably want to include your grouping fields in the new anonymous type as well:
var stats = /* ... */
select new
{
Call_Date = statsGroup.Key.c.Call_Date,
CompanyCharge = statsGroup.Key.cc.CompanyCharge,
Resolution = statsGroup.Key.r.Resolution,
Count = statsGroup.Count(),
Total = statsGroup.Sum(stat => stat.c.Duration),
};