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How to force delete COALESCE function in query. C# EntityFramework 7.0.2 LINQ

Ok, I have such SQL code:
DECLARE #documentId INT = 8
SELECT
i.[status] AS [status],
i.[barcode] AS [barcode],
i.[containerId] AS [containerTypeId],
(
SUM(ISNULL(lp.[Weight], 0) * il.[factCount]) +
ISNULL(lpt.[Weight], 0)
) AS [weight],
i.[comment] AS [comment]
FROM [Items] AS i WITH(NOLOCK)
LEFT JOIN [dbo].[ItemsLines] AS il WITH(NOLOCK) ON i.[id] = il.[itemsId]
LEFT JOIN [dbo].[LagerOptions] AS lp WITH(NOLOCK) ON lp.[lagerId] = il.[lagerId]
LEFT JOIN [dbo].[LagerOptions] AS lpt WITH(NOLOCK) ON lpt.[lagerId] = i.[containerId]
WHERE #documentId = i.[documentId]
GROUP BY i.[status], i.[barcode], i.[containerId], i.[comment], lpt.[Weight]
The most similar code I've written in LINQ is:
var lots = await (
from i in _dbContext.Items
join lpt in _dbContext.LagerOptions on i.ContainerId equals lpt.LagerId into lptTable
from lpt in lptTable.DefaultIfEmpty()
// The sum of all lagers for current lot
let lotWeight = (
from il in _dbContext.ItemsLines
join lp in _dbContext.LagerOptions on il.LagerId equals lp.LagerId into lpTable
from lp in lpTable.DefaultIfEmpty()
where il.ItemsId == i.Id
select (il.FactCount * lp.Weight.GetValueOrDefault(0))
).Sum()
where i.DocumentsId == documentId
select new
{
Status = i.Status,
Barcode = i.Barcode,
ContainerTypeId = i.ContainerId,
// total weight with container Weight
Weight = lotWeight + lpt.Weight.GetValueOrDefault(0),
//
Comment = i.Comment
}
).ToListAsync();
For SQL query the results can contain empty lots or lots with null-weight lagers (problem lagers) that makes "Weight" field of lot is equal NULL that helps detect problem lots.
But when I check the C# LINQ code EntityFramework create a COALESCE() function over SUM() function
and the query converted to SQL looks like this:
SELECT [t].[status] AS [Status], [t].[barcode] AS [Barcode], [t].[containerId] AS [ContainerTypeId], (
SELECT COALESCE(SUM([t0].[factCount] * COALESCE([l0].[Brutto], 0.0)), 0.0)
FROM [dbo].[ItemsLines] AS [t0]
LEFT JOIN [dbo].[LagerOptions] AS [l0] ON [t0].[lagerId] = [l0].[lagerId]
WHERE [t0].[itemsId] = [t].[id]) + COALESCE([l].[weight], 0.0) AS [Weight], [t].[comment] AS [Comment]
FROM [dbo].[Items] AS [t]
LEFT JOIN [dbo].[LagerOptions] AS [l] ON [t].[containerId] = [l].[lagerId]
WHERE [t].[documentId] = #__documentId_0
As a result, the weight of the problem lot will be equal to the container weight of this lot.
I can solve the problem with crutch methods, but I'm sure that there is a simple solution, which, unfortunately, I did not find.
I tryed to add different checks on null and rewrite the query for different JOIN patterns, but the main problem - EntityFramework create a COALESCE() function over SUM() function. And I don't know how to fix it in root. I work with C# EF approximately 1 month. EF 7.0.2
Help me, please.
!!EDITED
Correct LINQ query looks like this (Thank, Svyatoslav Danyliv):
var query =
from i in _dbContext.Items
join il in _dbContext.ItemsLines on i.Id equals il.ItemsId into ilj
from il in ilj.DefaultIfEmpty()
join lp in _dbContext.LagerOptions on il.LagerId equals lp.LagerId into lpj
from lp in lpj.DefaultIfEmpty()
join lpt in _dbContext.LagerOptions on i.ContainerId equals lpt.LagerId into lptj
from lpt in lptj.DefaultIfEmpty()
where i.DocumentsId == documentId
group new { lp, il, lpt } by new { i.Status, i.Barcode, i.ContainerId, i.Comment, lpt.Weight } into g
select new
{
g.Key.Status,
g.Key.Barcode,
ContainerTypeId = g.Key.ContainerId,
Weight = g.Sum(x => ((decimal?)x.lp.Weight) ?? 0 * x.il.FactCount) + g.Key.Weight ?? 0
g.Key.Comment,
};
But the query converted to SQL looks like this:
SELECT
[t].[status] AS [Status],
[t].[barcode] AS [Barcode],
[t].[containerId] AS [ContainerTypeId],
COALESCE(SUM(COALESCE([l].[weight], 0.0) * [t0].[factCount])), 0.0) +
COALESCE([l0].[weight], 0.0) AS [Weight],
[t].[comment] AS [Comment]
FROM [dbo].[Items] AS [t]
LEFT JOIN [dbo].[ItemsLines] AS [t0] ON [t].[id] = [t0].[itemsId]
LEFT JOIN [dbo].[LagerOptions] AS [l] ON [t0].[lagerId] = [l].[lagerId]
LEFT JOIN [dbo].[LagerOptions] AS [l0] ON [t].[containerId] = [l0].[lagerId]
WHERE [t].[documentsId] = #__documentId_0
GROUP BY [t].[status], [t].[barcode], [t].[containerId], [t].[comment], [l0].[weight]
EntityFramework create a COALESCE() function over SUM() function.
How to remove this?

This should equivalent LINQ query to your SQL. I do not understand why instead of grouping you have forced LINQ Translator to generate another query.
var query =
from i in _dbContext.Items
join il in _dbContext.ItemsLines on i.Id equals il.ItemsId into ilj
from il in ilj.DefaultIfEmpty()
join lp in _dbContext.LagerOptions on il.LagerId equals lp.LagerId into lpj
from lp in lpj.DefaultIfEmpty()
join lpt in _dbContext.LagerOptions on i.ContainerId equals lpt.LagerId into lptj
from lpt in lptj.DefaultIfEmpty()
where i.DocumentsId == documentId
group new { lp, il, lpt } by new { i.Status, i.Barcode, i.ContainerId, i.Comment, lpt.Weight } into g
select new
{
g.Key.Status,
g.Key.Barcode,
ContainerTypeId = g.Key.ContainerId,
Weight = g.Sum(x => ((double?)x.lp.Weight) ?? 0 * x.il.FactCount) + g.Key.Weight ?? 0
g.Key.Comment,
};

LINQ to SQL, multiple table join, generated SQL missing 2nd INNER JOIN

Can anyone tell me why the generated SQL does not contain a 2nd INNER JOIN? It seems to have been replaced with a NULL check in the WHERE clause? I'm not clear on why the 2nd INNER JOIN is not in the generated SQL.
C# code:
var cycleList = from o in entities.Orders
join c in entities.Cycles on o.Id equals c.OrderId
join calendar in entities.Calendars on c.CalendarId equals calendar.Id
where o.UnitId == unitId && o.CompanyId == companyId
select c.Id;
Generated SQL:
SELECT
[Extent2].[Id] AS [Id]
FROM [dbo].[Orders] AS [Extent1]
INNER JOIN [dbo].[Cycles] AS [Extent2] ON [Extent1].[Id] = [Extent2].[OrderId]
WHERE ([Extent2].[CalendarId] IS NOT NULL) AND ( CAST( [Extent1].[UnitId] AS int) = #p__linq__0) AND ( CAST( [Extent1].[CompanyId] AS int) = #p__linq__1)

It looks like the query generator is optimizing your query.
Since you are not selecting (or using in your where clause) any fields from the Calendars table in your query, only one join is done between the Orders table and the Cycles table. It's likely faster to check for the non-NULL foreign key than it is to join on a table from which no fields will be used.

LINQ multiple joins with one left join

I am fairly new to LINQ and I am struggling to make a multiple JOIN.
So, this is how my database structure looks like:
Now, how should my query look like, if I have a particular Grade and I want to select
{Student.IndexNo, GradeValue.Value}, but if there is no grade value for a particular grade and particular user, null should be returned (Left join)?

The trick to get a LEFT join is to use the DefaultIfEmpty() method:
var otherValue = 5;
var deps = from tbl1 in Table1
join tbl2 in Table2
on tbl1.Key equals tbl2.Key into joinGroup
from j in joinGroup.DefaultIfEmpty()
where
j.SomeProperty == "Some Value"
&& tbl1.OtherProperty == otherValue
select j;

Deliberately posting this in 2015 for newbies looking for solution on google hits. I managed to hack and slash programming my way into solution.
var projDetails = from r in entities.ProjekRumah
join d in entities.StateDistricts on r.ProjekLocationID equals d.DistrictID
join j in entities.ProjekJenis on r.ProjekTypeID equals j.TypeID
join s in entities.ProjekStatus on r.ProjekStatusID equals s.StatusID
join approvalDetails in entities.ProjekApproval on r.ProjekID equals approvalDetails.ProjekID into approvalDetailsGroup
from a in approvalDetailsGroup.DefaultIfEmpty()
select new ProjectDetailsDTO()
{
ProjekID = r.ProjekID,
ProjekName = r.ProjekName,
ProjekDistrictName = d.DistrictName,
ProjekTypeName = j.TypeName,
ProjekStatusName = s.StatusName,
IsApprovalAccepted = a.IsApprovalAccepted ? "Approved" : "Draft",
ProjekApprovalRemarks = a.ApprovalRemarks
};
Produces following SQL code internally
{SELECT [Extent1].[ProjekID] AS [ProjekID]
,[Extent1].[ProjekName] AS [ProjekName]
,[Extent2].[DistrictName] AS [DistrictName]
,[Extent3].[TypeName] AS [TypeName]
,[Extent4].[StatusName] AS [StatusName]
,CASE
WHEN ([Extent5].[IsApprovalAccepted] = 1)
THEN N'Approved'
ELSE N'Draft'
END AS [C1]
,[Extent5].[ApprovalRemarks] AS [ApprovalRemarks]
FROM [dbo].[ProjekRumah] AS [Extent1]
INNER JOIN [dbo].[StateDistricts] AS [Extent2] ON [Extent1].[ProjekLocationID] = [Extent2].[DistrictID]
INNER JOIN [dbo].[ProjekJenis] AS [Extent3] ON [Extent1].[ProjekTypeID] = [Extent3].[TypeID]
INNER JOIN [dbo].[ProjekStatus] AS [Extent4] ON [Extent1].[ProjekStatusID] = [Extent4].[StatusID]
LEFT JOIN [dbo].[ProjekApproval] AS [Extent5] ON [Extent1].[ProjekID] = [Extent5].[ProjekID]
}

Linq Join with a Group By

Ok, I am trying to replicate the following SQL query into a Linq expression:
SELECT
I.EmployeeNumber,
E.TITLE,
E.FNAM,
E.LNAM
FROM
Incidents I INNER JOIN Employees E ON I.IncidentEmployee = E.EmployeeNumber
GROUP BY
I.EmployeeNumber,
E.TITLE,
E.FNAM,
E.LNAM
Simple enough (or at least I thought):
var query = (from e in contextDB.Employees
join i in contextDB.Incidents on i.IncidentEmployee = e.EmployeeNumber
group e by new { i.IncidentEmployee, e.TITLE, e.FNAM, e.LNAM } into allIncEmps
select new
{
IncEmpNum = allIncEmps.Key.IncidentEmployee
TITLE = allIncEmps.Key.TITLE,
USERFNAM = allIncEmps.Key.FNAM,
USERLNAM = allIncEmps.Key.LNAM
});
But I am not getting back the results I exprected, so I fire up SQL Profiler to see what is being sent down the pipe to SQL Server and this is what I see:
SELECT
[GroupBy1].[A1] AS [C1]
FROM ( SELECT
COUNT(1) AS [A1]
FROM ( SELECT DISTINCT
[Extent2].[IncidentEmployee] AS [IncidentEmployee],
[Extent1].[TITLE] AS [TITLE],
[Extent1].[FNAM] AS [FNAM],
[Extent1].[LNAM] AS [LNAM]
FROM [dbo].[Employees] AS [Extent1]
INNER JOIN [dbo].[INCIDENTS] AS [Extent2] ON ([Extent1].[EmployeeNumber] = [Extent2].[IncidentEmployee]) OR (([Extent1].[EmployeeNumber] IS NULL) AND ([Extent2].[IncidentEmployee] IS NULL))
) AS [Distinct1]
) AS [GroupBy1]
As you can see from the SQL string that was sent toSQL Server none of the fields that I was expecting to be return are being included in the Select clause. What am I doing wrong?
UPDATE
It has been a very long day, I re-ran the code again and now this is the SQL that is being sent down the pipe:
SELECT
[Distinct1].[IncidentEmployee] AS [IncidentEmployee],
[Distinct1].[TITLE] AS [TITLE],
[Distinct1].[FNAM] AS [FNAM],
[Distinct1].[LNAM] AS [LNAM]
FROM ( SELECT DISTINCT
[Extent1].[OFFNUM] AS [OFFNUM],
[Extent1].[TITLE] AS [TITLE],
[Extent1].[FNAM] AS [FNAM],
[Extent1].[LNAM] AS [LNAM]
FROM [dbo].[Employees] AS [Extent1]
INNER JOIN [dbo].[INCIDENTS] AS [Extent2] ON ([Extent1].[EmployeeNumber] = [Extent2].[IncidentEmployee]) OR (([Extent1].[EmployeeNumber] IS NULL) AND ([Extent2].[IncidentEmployee] IS NULL))
) AS [Distinct1]
But I am still not seeing results when I try to loop through the record set
foreach (var emps in query)
{
}

Not sure why the query does not return what it should return, but it occurred to me that since you only query the group key and not any grouped results you've got nothing but a Distinct():
var query =
(from e in contextDB.Employees
join i in contextDB.Incidents on i.IncidentEmployee equals e.EmployeeNumber
select new
{
IncEmpNum = i.IncidentEmployee
TITLE = e.TITLE,
USERFNAM = e.FNAM,
USERLNAM = e.LNAM
}).Distinct();
But EF was smart enough to see this as well and created a DISTINCT query too.
You don't specify which result you expected and in what way the actual result was different, but I really can't see how the grouping can produce a different result than a Distinct.
But how did your code compile? As xeondev noticed: there should be an equals in stead of an = in a join statement. My compiler (:D) does not swallow it otherwise. The generated SQL join is strange too: it also matches records where both joined values are NULL. This makes me suspect that at least one of your keys (i.IncidentEmployee or e.EmployeeNumber) is nullable and you should either use i.IncidentEmployee.Value or e.EmployeeNumber.Value or both.

How to write linq query to prevent duplicates joins?

I have a query that search for all accommodations in an order, sorted by day. When I check on the sever what query is executed, I see multiple join toward the same table on the same keys
var parcourt = this.DataService.From<OrderItem>()
.Where(i => i.OrderId == orderId && i.Product.ProductTypeId == (int)ProductTypes.Accommodation)
.OrderBy(i => i.DayNumber)
.ThenBy(i => i.OrderItemId)
.Select(i => new
{
i.OrderItemId,
i.DayNumber,
i.Product.Establishment.Address,
i.Product.Establishment.Coordinates
});
If you check the resulting SQL (as show by ToTraceString), you can see two join on the Products and Establishments table.
SELECT
[Project1].[OrderItemId] AS [OrderItemId],
[Project1].[DayNumber] AS [DayNumber],
[Project1].[Address] AS [Address],
[Project1].[EstablishmentId] AS [EstablishmentId],
[Project1].[Latitude] AS [Latitude],
[Project1].[Longitude] AS [Longitude]
FROM ( SELECT
[Extent1].[OrderItemId] AS [OrderItemId],
[Extent1].[DayNumber] AS [DayNumber],
[Extent4].[Address] AS [Address],
[Extent5].[EstablishmentId] AS [EstablishmentId],
[Extent5].[Latitude] AS [Latitude],
[Extent5].[Longitude] AS [Longitude]
FROM [dbo].[OrderItems] AS [Extent1]
INNER JOIN [dbo].[Products] AS [Extent2] ON [Extent1].[ProductId] = [Extent2].[ProductId]
LEFT OUTER JOIN [dbo].[Products] AS [Extent3] ON [Extent1].[ProductId] = [Extent3].[ProductId]
LEFT OUTER JOIN [dbo].[Establishments] AS [Extent4] ON [Extent3].[EstablishmentId] = [Extent4].[EstablishmentId]
LEFT OUTER JOIN [dbo].[Establishments] AS [Extent5] ON [Extent3].[EstablishmentId] = [Extent5].[EstablishmentId]
WHERE (1 = [Extent2].[ProductTypeId]) AND ([Extent1].[OrderId] = #p__linq__0)
) AS [Project1]
ORDER BY [Project1].[DayNumber] ASC, [Project1].[OrderItemId] ASC
How can I prevent this linq-to-entities from joining twice on a table? How can I rewrite the query to avoid this situation?
The table structure goes as follow (simplified):
This is the query

Could you try this query? I think if you call all your joins explicitly, it'll not create joins automatically.
var parcourt = (from i in this.DataService.OrderItem
join p in this.DataService.Product on p.ProductId equals i.ProductId
join e in this.DataService.Establishments on e.EstablishmentId equals p.EstablishmentId
where i.OrderId == orderId && p.ProductTypeId == (int)ProductTypes.Accomodation
orderby i.DayNumber, i.OrderItemId
select new
{
i.OrderItemId,
i.DayNumber,
e.Address,
e.Coordinates
});