We Keep Coding

Join list with table in linq

I have a problem. I get all data in var type variable and then want to apply a join with database table in code first approach. Facing problem, lot of search on internet and apply but failed.
var joinedData =
from menuGroup in _menuGroupMenusRepository.GetAll()
.Where(x => x.GroupId == input.GroupId)
join menus in _menuRepository.GetAll()
on menuGroup.MenuId equals menus.Id
join categSubcateg in _menuCategSubCategRepository.GetAll()
on menus.Id equals categSubcateg.MenuId
join categ in _menuCategoryRepository.GetAll()
on categSubcateg.CategoryId equals categ.Id
select new
{
CategoryId = categSubcateg.CategoryId,
CategoryName = categ.Category,
};
Now I want joinedData variable join with MainMenuSort table.
MainMenuSort table also have groupid and categoryid.

to perform join you just need to do as below
var q=(from jd in joinedData
join mms in dataContext.MainMenuSort
on jd.CategoryId equals mms.CategoryId
select jd).ToList();
if its datatable then
var q=(from jd in joinedData
join mms in dtMainMenuSort.AsEnumerable()
on jd.CategoryId equals mms.Field<int>("CategoryId")
select jd).ToList();

LINQ Left Join with multiple ON OR conditions

I'm sorry for telling that I've a little bit weak on LINQ, I always do write SQL query before I start working on the complicated LINQ.
I want to ask that how to convert this SQL Query into LINQ with LEFT JOIN with multiple ON conditons with the OR operator.,
m.MerchandiseId will be use for twice in ON condition
SELECT
*
FROM
Inbox AS i
INNER JOIN [User] AS u ON i.FromUserId = u.UserId
LEFT OUTER JOIN Merchandise AS m ON
u.MerchandiseId = m.MerchandiseId
OR
i.ToMerchantId = m.MerchandiseId
WHERE
i.ToCompanyId = 10
OR
i.FromCompanyId = 10
var message = (from i in db.Inbox
join u in db.User on i.FromUserId equals u.UserId
join m in db.Merchandise on u.MerchandiseId equals m.MerchandiseId //here I want to ON i.MerchantId = m.MerchandiseId, but it doesn't allow
where i.ToCompanyId == user.CompanyId || i.FromCompanyId == user.CompanyId
orderby i.CreatedAt descending
group m.MerchandiseId by new { m.MerchandiseId, m.MerchandiseName } into grp
select new
{
MerchandiseId = grp.Key.MerchandiseId,
MerchandiseName = grp.Key.MerchandiseName,
InboxMessage = (from e in db.Inbox
join us in db.User on e.FromUserId equals us.UserId
join mer in db.Merchandise on us.MerchandiseId equals mer.MerchandiseId
where mer.MerchandiseId == grp.Key.MerchandiseId
orderby e.CreatedAt descending
select e.InboxMessage).FirstOrDefault(),
CreatedAt = (from e in db.Inbox
join us in db.User on e.FromUserId equals us.UserId
join mer in db.Merchandise on us.MerchandiseId equals mer.MerchandiseId
where mer.MerchandiseId == grp.Key.MerchandiseId
orderby e.CreatedAt descending
select e.CreatedAt).FirstOrDefault(),
}).ToList();
The bottom LINQ Query I've write for it. However, I just can work on the left join with multiple ON clause in LINQ. Appreciate if someone would help me on this. Thanks!

I don't believe Linq supports the use of the OR operator with multiple columns, but that said, I wouldn't use OR even in SQL as it makes the join's intention unclear and it also obscures where the data originated from - it also isn't immediately clear what happens if there are multiple matches for each column. Instead I would JOIN twice on the different columns and let the projection-clause handle it:
SELECT
*
FROM
Inbox
INNER JOIN [User] AS u ON i.FromUserId = u.UserId
LEFT OUTER JOIN Merchandise AS userMerchant ON u.MerchandiseId = userMerchant.MerchandiseId
LEFT OUTER JOIN Merchandise AS inboxMerchant ON Inbox.ToMerchantId = inboxMerchant .MerchandizeId
WHERE
Inbox.ToCompanyId = 10
OR
Inbox.FromCompanyId = 10
This can then be translated into Linq using the LEFT OUTER JOIN approach ( How to implement left join in JOIN Extension method )
Note that if you're using Entity Framework then you don't need to worry about doing any of this at all! Just use Include:
var query = db.Inbox
.Include( i => i.User )
.Include( i => i.User.Merchandise )
.Include i => i.Merchandise )
.Where( i => i.ToCompanyId = 10 || i.FromCompanyId == 10 );

Linq to sql Distinct after join

I have a join query and i want to filter the result of this query by using distinct. I want to get only one of the shoes which has same brand, model, primary color and secondary color. How can i make this ? Here is my join query.
var query = from b in db.BrandTbls.AsQueryable()
join m in db.ShoeModelTbls on b.BrandID equals m.BrandID
join s in db.ShoeTbls on m.ModelID equals s.ModelID
join i in db.ShoeImageTbls on s.ShoeID equals i.ShoeID
where s.Quantity > 0
orderby m.ModelName
select new
{
s.ShoeID,
m.ModelName,
m.Price,
b.BrandName,
i.ImagePath
};

I found the solution. This query does approximately what i want to do
var query = from b in db.BrandTbls.AsQueryable()
join m in db.ShoeModelTbls on b.BrandID equals m.BrandID
join s in db.ShoeTbls on m.ModelID equals s.ModelID
join i in db.ShoeImageTbls on s.ShoeID equals i.ShoeID
group new {b,m,s,i} by new {b.BrandName,m.ModelName,m.Price,s.ShoeID,s.PrimaryColor,s.SecondaryColor,i.ImagePath} into g
select new {g.Key.ShoeID,g.Key.BrandName,g.Key.ModelName,g.Key.ImagePath,g.Key.Price};

Remove price from the output and use Distinct() like this:
var query = (from b in db.BrandTbls.AsQueryable()
join m in db.ShoeModelTbls on b.BrandID equals m.BrandID
join s in db.ShoeTbls on m.ModelID equals s.ModelID
join i in db.ShoeImageTbls on s.ShoeID equals i.ShoeID
where s.Quantity > 0
orderby m.ModelName
select new
{
s.ShoeID,
m.ModelName,
b.BrandName,
i.ImagePath
}).Distinct();

LINQ: Inner join 2 table + outer join 1 table

I have 2 inner joins (3 tables) but I don't know and I find it hard to implement my research about outer join in LINQ. How do I change the last inner join to outer join, such that column will still join even if the column (Role) is null?
Here's an existing SQL version of this which I want to convert to LINQ:
SELECT dbo.EmployeeAccess.id, dbo.EmployeeAccess.EmpNo, dbo.EmployeeAccess.RoleID, dbo.EmployeeAccess.Active, dbo.EmployeeAccessLevel.Role,
dbo.View_HCM.LNameByFName
FROM dbo.EmployeeAccess LEFT OUTER JOIN
dbo.EmployeeAccessLevel ON dbo.EmployeeAccess.RoleID = dbo.EmployeeAccessLevel.id INNER JOIN
dbo.View_HCM ON dbo.EmployeeAccess.EmpNo = dbo.View_HCM.EmpNo
LINQ I now have with 2 inner joins:
(from ea in context.EmployeeAccesses
join vh in context.View_HCM on (Int16)ea.EmpNo equals vh.EmpNo
join rl in context.EmployeeAccessLevels on ea.RoleID equals rl.id
select new EmployeeWithEmail{
EmpNum = ea.EmpNo ?? 0,
EmailAddress = vh.EmailAddress,
LNameByFname = vh.LNameByFName,
Active2 = ea.Active ?? false
}).ToList();
}

Linq's outer join syntax uses 2 parts. First an into then DefaultIfEmpty
In your case, an outer join might look like this:
(from ea in context.EmployeeAccesses
join vh in context.View_HCM on (Int16)ea.EmpNo equals vh.EmpNo
join rl in context.EmployeeAccessLevels on ea.RoleID equals rl.id into outer_join
from subjoin in outer_join.DefaultIfEmpty()
select new EmployeeWithEmail{
EmpNum = ea.EmpNo ?? 0,
EmailAddress = vh.EmailAddress,
LNameByFname = vh.LNameByFName,
Active2 = ea.Active ?? false
}).ToList();
There are many tutorials on how to create the outer join in LINQ.

LINQ and joining on selects

I have the following SQL:
select o.tekst as Enhet,
coalesce(f.Antall,0) as AntallF,
coalesce(f.snitt,0) as SnittF,
coalesce(b.antall,0) as AntallB
from tblhandlingsplan hp
inner join tblorg o on hp.eierorgid = o.orgid
left outer join (select f.handlingsplanid, count(t.tiltakid) as Antall, coalesce(avg(convert(float,t.status)),0) as Snitt from tblhandlingsplanforbedring f left outer join tblhandlingsplantiltak t on f.forbedringsid = t.forbedringsid group by f.handlingsplanid) f on hp.handlingsplanid = f.handlingsplanid
left outer join (select b.handlingsplanid, count(b.bevaringsid) as Antall from tblhandlingsplanbevaring b group by b.handlingsplanid) b on hp.handlingsplanid = b.handlingsplanid
where utsendingsid = 1
Which works exactly how I want it... Now I'm trying to convert this to LINQ...
I have gotten this far
from h in TblHandlingsplans
join o in TblOrgs
on h.EierOrgID equals o.OrgID
join f in TblHandlingsplanForbedrings
on h.HandlingsplanID equals f.HandlingsplanID into f2
join b in TblHandlingsplanBevarings
on h.HandlingsplanID equals b.HandlingsplanID into b2
where h.UtsendingsID == 1
select new {
Enhet = o.Tekst,
AntallF = f2.Count(),
AntallB = b2.Count()
}
however now I'm stuck... I can't for the life of me figure out how to include the average part from the SQL solution... Any takers?
I'm thinking of shoving the whole thing into a SP and leave it with that...

var query1 = from a in DB.Table1
select new
{
Id = a.Id,
Average = a.B.Average()
};
var query2 = from b in DB.Table2
join c in query1 on b.Id equals c.Id
select c;
Just freehanded it, so it might not actually work, but is that the kind of thing you're trying to do? That would result in a single SQL query being created when query2 was used.