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How to make left join and group by in linq?

I want to join 3 tables 2 of them inner join one of them left join after that i want to make group by. However, it gives an error. How can I handle that ?
this is code :
var people = from u in db.User.ToList()
join o in db.Offer.ToList() on u.UserId equals o.UserID where o.Statu == "Accepted"
join oz in db.log.ToList() on new { x1 = u.UserId.ToString(), x2 = o.CampaignId.ToString() } equals new { x1 = oz.ID, x2 = oz.CampaignID } into ps
from tbl in ps.DefaultIfEmpty()
group new { u, o, tbl } by new { u.UserId, o.CampaignId, o.Target, tbl.ID} into grp
select new { Username = grp.Key.UserId, CampaignID= grp.Key.CampaignId, Target = grp.Key.Target, id = grp.Key.ID};
Error occurs when i use tbl in group by. But i need to use it. I think some values comes null so it gives an error. How can i handle this ?

T-SQL to LINQ query that has a case statement and a subquery in it

I'm a complete beginner in LINQ and I would like to convert this T-SQL query in LINQ
SELECT
CASE
WHEN D.IsBaseloadDefined = 1
THEN COUNT(D.DeviceID)
ELSE
(SELECT COUNT(DORG.DeviceID)
FROM DeviceOrganization DORG
INNER JOIN Organization ORG ON DORG.OrganizationID = ORG.OrganizationID
INNER JOIN BaseloadOrganization BO ON ORG.BaseloadOrganizationId = BO.OrganizationID
INNER JOIN Baseload BL ON BO.BaseloadID = BL.BaseloadID
WHERE DORG.DeviceID = D.DeviceID
AND BL.RecursUntil >= GETDATE()
GROUP BY DORG.DeviceID)
END AS [Nb of devices]
FROM DeviceOrganization DO
INNER JOIN Device D ON DO.DeviceID = D.DeviceID
LEFT JOIN BaseloadDevice BD ON D.DeviceID = BD.DeviceID
LEFT JOIN Baseload B ON BD.BaseloadID = B.BaseloadID AND B.RecursUntil >= GETDATE()
INNER JOIN OrganizationHierarchy OH ON DO.OrganizationID = OH.SubOrganizationID
WHERE OH.OrganizationID = 6
AND D.IsActive = 1
group by D.DeviceID, D.IsBaseloadDefined
I've seen this topic but I don't really understand the answer
The only thing I could do so far is this, and now I'm completly lost
from deviceO in _context.DeviceOrganizations
join d in _context.Devices on deviceO.DeviceID equals d.DeviceID
join bd in _context.BaseloadDevices on d.DeviceID equals bd.DeviceID
join b in _context.Baseloads on bd.BaseloadID equals b.BaseloadID
join oh in _context.OrganizationHierarchies on deviceO.OrganizationID equals oh.SubOrganizationID
where oh.OrganizationID == OrganizationId
where d.IsActive == true
where b.RecursUntil <= DateTime.Now
group d.DeviceID by d.DeviceID).Count()

Instead of get count of group
group d.DeviceID by d.DeviceID).Count()
you should save result in variable
var data = from deviceO in _context.DeviceOrganizations
join d in _context.Devices on deviceO.DeviceID equals d.DeviceID
join bd in _context.BaseloadDevices on d.DeviceID equals bd.DeviceID
join b in _context.Baseloads on bd.BaseloadID equals b.BaseloadID
join oh in _context.OrganizationHierarchies on deviceO.OrganizationID equals oh.SubOrganizationID
where oh.OrganizationID == OrganizationId
where d.IsActive == true
where b.RecursUntil <= DateTime.Now
and then you should do something like this:
//group by 2 properties
var result = data.GroupBy(d => new { d.DeviceID, d.IsBaseloadDefined })
.Select(g =>
{
//for each group we get IsBaseloadDefined property
var IsBaseloadDefined = g.Key.IsBaseloadDefined;
if (IsBaseloadDefined == 1)
{
return g.Count();
}
else
{
// here another select that return count:
//(SELECT COUNT(DORG.DeviceID)
//FROM DeviceOrganization DORG
// INNER JOIN Organization ORG ON DORG.OrganizationID = ORG.OrganizationID
//INNER JOIN BaseloadOrganization BO ON ORG.BaseloadOrganizationId = BO.OrganizationID
//INNER JOIN Baseload BL ON BO.BaseloadID = BL.BaseloadID
//WHERE DORG.DeviceID = D.DeviceID
//AND BL.RecursUntil >= GETDATE()
//GROUP BY DORG.DeviceID)
//in this query you should return Count() of group
return 1; //return group.Count() instead 1
}
});
I hope this helps you

Translate nested select of oracle query to linq

I was given an oracle query and am trying to translate it to linq. I have been successful up to the point of the inner select.
select distinct pm.projNumber, nvl(s.submission_nbr, ppo.submission_nbr) submission_nbr, nvl(ot.objectname, pot.objectname) objectname , wa.assigned, f.lname, f.fname
from wfassignment wa
join CodeTab c on c.codeid = wa.appr_stat
join projobject po on po.objectid = wa.objectid
join projmain pm on pm.projid = po.projid
join hhistory s on s.Prop_no = pm.Prop_No and s.Inst_Code = pm.Inst_Code and pm.System = 'foo' and s.mark = po.mark
left join objecttypes ot on ot.objecttype = po.objecttype and ot.system = pm.system
left join(
select a.mark, a.objecttype, a.submitdate, c.submission_nbr
from projobject a
join b on b.projid = a.projid
join c on c.Prop_no = b.Prop_No and c.Inst_Code = b.Inst_Code and b.System = 'foo' and c.mark = a.mark ) ppo on ppo.mark = s.parentmark
left join objecttypes pot on pot.objecttype = ppo.objecttype and pot.system = pm.system
join faculty f on f.unique_id = wa.unique_id
where wa.completed is null and wa.unique_id in ('foo', 'bar', 'foo', 'bar')
below is my C# code up until "left join (select... )"
var pageObject = (
from wa in db.WFASSIGNMENTs
join c in db.CODETABs on wa.APPR_STAT equals c.CODEID
join po in db.PROJOBJECTs on wa.OBJECTID equals po.OBJECTID
join pm in db.PROJMAINs on po.PROJID equals pm.PROJID
join s in db.HHISTORies on new { pm.PROP_NO, pm.INST_CODE, po.MARK } equals new { s.PROP_NO, s.INST_CODE, s.MARK }
join ot in db.OBJECTTYPES on new { OBJECTTYPE = po.OBJECTTYPE, pm.SYSTEM } equals new { OBJECTTYPE = ot.OBJECTTYPE1, ot.SYSTEM }
How do I translate the inner select to linq?

I pulled out the inner select into another variable and just joined that variable. Did the trick.

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.

entity framework query, how to select more than 1 table?

i have this query
var resultado = from c in conn.carrera
join u in conn.usuario on c.idusuario equals u.idusuario
join t in conn.texto on c.idtexto equals t.idtexto
where c.estatus == 1
select c;
how do i get something as it:
select c.*,u.*,t.eltexto from carrera c
join usuario u on c.idusuario =u.idusuario
join texto t on c.idtexto = t.idtexto
where c.estatus = 1
you could see in the query i am select c.*, u.* and t.col1, then
how can i get it in EF? because my first query gets only carrera.* but i need more data.
thanks

You could easily return a new object consisting all the properties of the three joined tables:
var resultado = from c in conn.carrera
join u in conn.usuario on c.idusuario equals u.idusuario
join t in conn.texto on c.idtexto equals t.idtexto
where c.estatus == 1
select new
{
c.prop_1,
c.prop_n,
u.prop_1,
u.prop_n,
t.prop_1,
t.prop_n
};

select c.*,u.*,t.eltexto from carrera c
join usuario u on c.idusuario =u.idusuario
join texto t on c.idtexto = t.idtexto
where c.estatus = 1
from c in Carrerra
join u in Usuario on c.idusuario equals u.idusuario
join t in Texto on c.idtexto equals t.idtexto
where c.estatus = 1
select new {
newcolumn1 = c.column1,
c.column2,
usercolumn1 = u.column1,
usercolumn2 = u.column2,
textcolumn = t.column1
}
if you want access to the objects themselves, then you could do
select new {
usario = u,
carrera = c,
texto = t
}
Carrera, Usario, and Texto refer to the Models in your Entity Framework container.