I have this scenario that I didnt find any solution looking through related SO questions :
(from TD as tx
join P as px on tx.field1= px.ID
join Q as rp on tx.field2 = rp.ID
join L as lc on tx.field3= lc.ID
group by tx.field1,
tx.field2,
L.randomfield4,
....a bunch of fields from P,Q,L
)as groupItem
left outer join M on groupItem.field1=M.ID
select new { */ Elements from groupItem and M /*}
My Linq looks as follows :
from tx in TD
join itemP in P on tx.field1 equals P.ID
join itemQ in Q on tx.field2 equals P.ID
join itemL in L on tx.field3 equals P.ID
group new { tx.field1 ,tx.field2 ,L.randomfield4 } by new { **fields from tx,p,q,etc} into groupItem
join dM in M on ????
If i try to select elements from groupItems I cannot access proprieties (because i didnt select anything ).
Can anyone help me with a starting point to this issue ? Also help me with a better name for the question :)
Hopefully I understood your question correctly but here is my answer. I divided the query into two so its easy to understand just combine them together if you fully get into it.
Basically the variable "groupedCollection" is your first joins and your grouping which basically includes the following collections TD, P, Q and L. Then the second variable "finalCollection" is your left outer join which give the result you need.
var groupedCollection = from tx in TD
join itemP in P on tx.field1 equals itemP.ID
join itemQ in Q on tx.field2 equals itemQ.ID
join itemL in L on tx.field3 equals itemL.ID
group new
{
//Select the collections you want to group it by
P,
Q,
L,
TD
}
by new
{
//Select fields you want to output group by here
tx.field1,
tx.field2,
tx.field3,
itemL.RandomField4
}
into g
select new
{
//Use ky to get your properties as they are already grouped by
yourField1 = g.Key.field1,
yourField2 = g.Key.field2,
yourField3 = g.Key.field3,
yourField4 = g.Key.RandomField4
};
var finalCollection = from dM in M
//This is your Left Outer Join
join xx in groupedCollection on dM.ID equals xx.yourField1 into sr
from w in sr.DefaultIfEmpty()
//Until here
select new
{
finalResultID = dM.ID,
finalField1 = w.yourField1,
finalField2 = w.yourField2,
finalField3 = w.yourField3,
finalField4 = w.yourField4
};
for more LINQ stuff this will give you an idea
http://anyrest.wordpress.com/2010/09/27/linq-to-sql-essentials/
Related
I have this query
SELECT t.NomeTipo, sum(v.QtdProduto)
FROM [dbo].[Vendas] AS V
RIGHT JOIN [dbo].[Produtos] AS P ON V.IdProduto = P.IdProduto
INNER JOIN [dbo].[Tipos] AS T ON P.IdTipo = T.IdTipo
group by t.NomeTipo
order by t.NomeTipo
I have tried this
var queryTipos = from vendas in repositorioVendas.Vendas
join produtos in repositorioProduto.Produtos.DefaultIfEmpty()
on vendas.IdProduto equals produtos.IdProduto
join tipos in repositorioTipo.Tipos
on produtos.IdTipo equals tipos.IdTipo
group vendas by new { tipos.NomeTipo, vendas.QtdProduto }
into novoGrupo
select new
{
NomeTipo = novoGrupo.Key.NomeTipo,
QtdProduto = novoGrupo.Sum(x => x.QtdProduto)
};
With this query I got only two results, but when I run straight from the database I get something like this:
Bebidas 16
Bolos 14
Frios 16
Pães 21
The trick is to realize that you can rewrite your query with a left join instead of a right join by swapping the order of the first two tables and that Linq doesn't have a way to really handle right joins. Also you're grouping was wrong.
var queryTipos = from produtos in repositorioProduto.Produtos
join vendas_pj in repositorioVendas.Vendas
on vendas_pj.IdProduto equals produtos.IdProduto into joined
from vendas in joined.DefaultIfEmpty()
join tipos in repositorioTipo.Tipos
on produtos.IdTipo equals tipos.IdTipo
group vendas by tipos.NomeTipo
into novoGrupo
select new
{
NomeTipo = novoGrupo.Key,
QtdProduto = novoGrupo.Sum(x => x.QtdProduto)
};
Basically a Left join in SQL
From TableA
Left Join TableB
On TableA.ID = TableB.ID
is done in Linq like this
from a in repo.TableA
join b_pj in repo.TableB
on a.ID equals b_pj.ID into joined
from b in joined.DefaultIfEmpty()
I'm trying to join few tables using LINQ and retrieve a data set. But my problem is when I group the tables, I cannot access the fields of the non grouped tables in the LINQ query. here is my sample code block. Please help
var query = from sb in db.Surfboards
join csb in db.CustomerSurfBoards on sb.SurfBoardID equals csb.SurfBoardID
join c in db.Customers on csb.CustomerID equals c.CustomerID
where c.IsActive
group new { sb,csb} by new {sb.ID, csb.ComponentId} into g
select new ReportModel()
{
ReceivedDate = g.First().Name,
Number = c.First().Number <------- this cannot be accessed
}
what I'm trying to achieve is something like this
select sb.Id, max(c.Number), cbs.Id from Surfboards as sb
inner join CustomerSurfBoards as cbs on sb.SurfBoardID = csb.SurfBoardID
inner join Customers as c on csb.CustomerID = c.CustomerID
group by sb.Id, csb.ComponentId
Try this:
var query = from sb in db.Surfboards
join csb in db.CustomerSurfBoards on sb.SurfBoardID equals csb.SurfBoardID
join c in db.Customers on csb.CustomerID equals c.CustomerID
where c.IsActive
select new {sb.id, c.number, cbs.componentid} into tmp
from t in tmp
group t by new {t.ID, t.ComponentId} into g
select new
{
g.Key.id, g.Key.componentid, number = g.Select(n=>n.number).OrderByDescending().FirstOrDefault()
}
I am using LinqToDB to help query a SQLite Database, however, I am having an issue where I need to do a join in a collection of joins. Here is what I have so far.
var craftList = from c in db.GetTable<Craft>()
join cP in db.GetTable<CraftProduct>() on c.ID equals cP.CraftID into cPS
join cM in db.GetTable<CraftMaterial>() on c.ID equals cM.CraftID into cMS
select new
{
Craft = c,
CraftProducts = cPS,
CraftMaterials = cMS
};
I need to do add to the groups cPS & cMS and have each element join with another table. Here is an example query that kind of shows you what needs to be done with the elements in cMS.
var materialList = from cM in db.GetTable<CraftMaterial>()
join i in db.GetTable<Item>() on cM.ItemID equals i.ID
select CraftMaterial.Build(cM, i);
I was able to figure out what I needed to do after some messing around, I just needed to do multiple queries.
var craftList = from craft in db.GetTable<Craft>()
join craftProduct in db.GetTable<CraftProduct>() on craft.ID equals craftProduct.CraftID into
craftProducts
join craftMaterial in db.GetTable<CraftMaterial>() on craft.ID equals craftMaterial.CraftID into
craftMaterials
select new
{
Craft = craft,
CraftProducts = from craftProduct in craftProducts
join item in db.GetTable<Item>() on craftProduct.ItemID equals item.ID
select CraftProduct.Build(craftProduct, item),
CraftMaterials = from craftMaterial in craftMaterials
join item in db.GetTable<Item>() on craftMaterial.ItemID equals item.ID
select CraftMaterial.Build(craftMaterial, item)
};
var query = from r in db.Resource
join c in db.ResourceProjectedCapacity on r.ID equals c.ResourceID into ps
from c in ps.DefaultIfEmpty(null)
join p in db.Project on c.ProjectID equals p.ID
select new
{
Capacity = c,
Resource = r,
Project = p
};
I have this linq query but it is only returning resources that have a matching row on ResourceProjectedCapacity table. How can I get all resources and in case they dont have a matching record the Capacity object to be null?
from i in db.Resource
let c = db.ResourceProjectedCapacity.Where(cc => i.id == cc.ResourceID).FirstOrDefault()
let p = db.Project.Where(pp => c.ProjectID == pp.ID).FirstOrDefault()
select new
{
Capacity = C,
Resource = i,
Project = p
}
try above code
I think the secondary inner join messes up the left outer join above it. I think a way to work around it is to break the join into a seperate query, and then left join on that, something like this:
var subquery = from c in db.ResourceProjectedCapacity
join p in db.Project on c.ProjectID equals p.ID
select new { c, p };
var query = from r in db.Resource
join c in subquery on r.ID equals c.c.ResourceID into ps
from c in ps.DefaultIfEmpty(null)
select new
{
Capacity = c.c,
Resource = r,
Project = c.p
};
NB don't worry, it won't do two db queries, it'll only execute against your db once you evaluate query with a .ToList() or something like that.
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.