i need select some fields from a table in the query using join, but in the select new statement i dont have acess from the fields of the join table.
var query = from p in persistencia.RequisicaoCompraItems
join s in persistencia.Suprimentos on p.SuprimentoID equals s.SuprimentoID
(i need get fields from this join)
group p by new {p.SuprimentoID, p.RequisicaoCompraItemID, p.RequisicaoCompraID } into x
from res in x
orderby x.Key.SuprimentoID
select new {res.SuprimentoID ,
res.RequisicaoCompraItemID,
**but in here i cant acess** };
Cheers**
They're in res.Key.SuprimentoID etc
Related
I've this query that i'm trying to put as linq:
select *
from stuff
inner join stuffowner so on so.stuffID = stuff.stuffID
left outer join (select min(loanId) as loanId, stuffownerId from loan
where userid = 1 and status <> 2 group by stuffownerId) t on t.stuffownerid = so.stuffownerid
left outer join loan on t.LoanId = loan.LoanId
when this is done, I would like to do a linq Group by to have Stuff has key, then stuffowners + Loan as value.
I can't seem to get to a nice query without sub query (hence the double left outer).
So basically what my query does, is for each stuff I've in my database, bring the owners, and then i want to bring the first loan a user has made on that stuff.
I've tried various linq:
from stuff in Stuffs
join so in StuffOwners on stuff.StuffId equals so.StuffId
join tLoan in Loans on so.StuffOwnerId equals tLoan.StuffOwnerId into tmpJoin
from tTmpJoin in tmpJoin.DefaultIfEmpty()
group tTmpJoin by new {stuff} into grouped
select new {grouped, fluk = (int?)grouped.Max(w=> w.Status )}
This is not good because if I don't get stuff owner and on top of that it seems to generate a lot of queries (LinqPad)
from stuff in Stuffs
join so in StuffOwners on stuff.StuffId equals so.StuffId
join tmpLoan in
(from tLoan in Loans group tLoan by tLoan.StuffOwnerId into g
select new {StuffOwnerId = g.Key, loanid = (from t2 in g select t2.LoanId).Max()})
on so.StuffOwnerId equals tmpLoan.StuffOwnerId
into tmptmp from tMaxLoan in tmptmp.DefaultIfEmpty()
select new {stuff, so, tmptmp}
Seems to generate a lot of subqueries as well.
I've tried the let keyworkd with:
from tstuffOwner in StuffOwners
let tloan = Loans.Where(p2 => tstuffOwner.StuffOwnerId == p2.StuffOwnerId).FirstOrDefault()
select new { qsdq = tstuffOwner, qsdsq= (int?) tloan.Status, kwk= (int?) tloan.UserId, kiwk= tloan.ReturnDate }
but the more info i get from tLoan, the longer the query gets with more subqueries
What would be the best way to achieve this?
Thanks
I have a Linq queries that have tables join and couple of tables inner join together. Sometimes I got an error from the query when table is empty. What I trying to do is I am tryting to get a value from table even if other table is empty.
Thanks in Advance.
You need to do left join
Assuming left join between customer and order table.
var query =
from customer in dc.Customers
from order
in dc.Orders
.Where(o => customer.CustomerId == o.CustomerId)
.DefaultIfEmpty()
select new { Customer = customer, Order = order }
Also refer below link
http://forums.asp.net/t/1792428.aspx/1
I need to write Join statment after writing query in linq
example :
var Query = (from Tab in Db.Employees
select Tab)
as i have some cases to perform join operation so
i need to do it on this Query Query.Join(Join with another Table like Department); I need the Syntax
if (DeptID != -1){ Query.Join(Join with table Department where FkDeptID = DeptID); }
Consider the usage of join in the LINQ 'query syntax':
from t1 in db.Table1
join t2 in db.Table2 on t1.field equals t2.field
select new { t1.field2, t2.field3}
Something like this?
var results = (from q in Query
join m in myList on q.SomeID = m.SomeID
select unknown);
Try using this query:
var Query =
from e in Db.Employees
join d in Db.Departments on e.FkDeptID equals d.DeptID into departments
select new
{
Employee = e,
Department = departments.SingleOrDefault(),
};
This works assuming that when e.FkDeptID == -1 that there is no record in the Departments table and in that case Department would be assigned null.
You should never have more than one department for an employee so I've used SingleOrDefault rather than FirstOrDefault.
How to select all columns from tables in join using linq
Sql:
select CTRL_RUN_JOB.*, CTRL_DATA_STREAM.*
from CTRL_RUN_JOB inner join CTRL_DATA_STREAM
on CTRL_RUN_JOB.DATA_STREAM_ID= CTRL_DATA_STREAM.DATA_STREAM_ID
Linq:
from CTLJCRJOB in CTRL_RUN_JOBs
join CTLRFDSTM in CTRL_DATA_STREAMs
on CTLJCRJOB.DATA_STREAM_ID equals CTLRFDSTM.DATA_STREAM_ID
select new {
CTLJCRJOB.* // ???
,CTLRFDSTM.* // ???
}
Thanks
While you cant expand them to columns, you can simply return the entities. Eg:
select new { CTLJCRJOB, CTLRFDSTM }
If you need it flattened, then you will have to write out the mapping yourself, but will still be very trivial.
You could use the into clause, but it will not flatten it for you.
from CTLJCRJOB in CTRL_RUN_JOBs
join CTLRFDSTM in CTRL_DATA_STREAMs
on CTLJCRJOB.DATA_STREAM_ID equals CTLRFDSTM.DATA_STREAM_ID into ALLCOLUMNS
from entry in ALLCOLUMNS
select entry
Another twist is
OutPutList = (from CTLJCRJOB in CTRL_RUN_JOBs
join CTLRFDSTM in CTRL_DATA_STREAMs
on CTLJCRJOB.DATA_STREAM_ID equals CTLRFDSTM.DATA_STREAM_ID
select CTLJCRJOB).ToList();
You could use the into clause, but it will not flatten it for you.
from CTLJCRJOB in CTRL_RUN_JOBs
join CTLRFDSTM in CTRL_DATA_STREAMs
on CTLJCRJOB.DATA_STREAM_ID equals
CTLRFDSTM.DATA_STREAM_ID into ALLCOLUMNS
from entry in ALLCOLUMNS
select entry
in this way we can only get CTLJCRJOB columns result, there was no CTLRFDSTM table columns through my test
I have the following Linq statement:
(from order in Orders.AsEnumerable()
join component in Components.AsEnumerable()
on order.ORDER_ID equals component.ORDER_ID
join detail in Detailss.AsEnumerable()
on component.RESULT_ID equals detail.RESULT_ID
where orderRestrict.ORDER_MNEMONIC == "MyOrderText"
select new
{
Mnemonic = detail.TEST_MNEMONIC,
OrderID = component.ORDER_ID,
SeqNumber = component.SEQ_NUM
}).ToList()
I expect this to put out the following query:
select *
from Orders ord (NoLock)
join Component comp (NoLock)
on ord .ORDER_ID = comp.ORDER_ID
join Details detail (NoLock)
on comp.RESULT_TEST_NUM = detail .RESULT_TEST_NUM
where res.ORDER_MNEMONIC = 'MyOrderText'
but instead I get 3 seperate queries that select all rows from the tables. I am guessing that Linq is then filtering the values because I do get the correct values in the end.
The problem is that it takes WAY WAY too long because it is pulling down all the rows from all three tables.
Any ideas how I can fix that?
Remove the .AsEnumerable()s from the query as these are preventing the entire query being evaluated on the server.