id'like to count how many documents a User edited or created. Therefore I have a Datatable which contains the information sth. like this:
Input
DocumentName | ModifiedBy | CreatedBy
a Frank Frank
b Mike Frank
c John Mike
That should be the Output:
Name DocumentsModified(Total) DocumentsCreated(Total)
Frank 1 2
Mike 1 1
John 1 0
So what it did to count all documents a person edited, is the following
var query = from queryResult in resultTable.AsEnumerable()
group queryResult by queryResult.Field<string>("ModifiedBy") into rowGroup
select new
{
Name = rowGroup.Key, ModifiedDocuments = rowGroup.Count()
};
This works fine. Now i have to count also the values of the column "Creator". Is this possible and if so, how would i do that? OK, i could iterate over the table, but it would be nice to accomplish this in the LinQ query.
I tried to use "group queryResult by new {}" but i'm not sure if i'm on the right track.
You're best bet would be to just query for created and modified separately and then combine the results with a join.
var modifiedCount = from queryResult in resultTable.AsEnumerable()
group queryResult by queryResult.Field<string>("ModifiedBy") into rowGroup
select new
{
Name = rowGroup.Key, ModifiedDocuments = rowGroup.Count()
};
var createdCount = from queryResult in resultTable.AsEnumerable()
group queryResult by queryResult.Field<string>("CreatedBy") into rowGroup
select new
{
Name = rowGroup.Key, CreatedDocuments = rowGroup.Count()
};
var finalResult = from first in modifiedCount
join second in createdCount
on first.Name equal second.Name
select new
{
first.Name,
first.ModifiedDocuments,
second.CreatedDocuments
};
Can't you use the same method with CreatedBy?
var query2 = from queryResult in resultTable.AsEnumerable()
group queryResult by queryResult.Field<string>("CreatedBy") into rowGroup
select new
{
Name = rowGroup.Key, ModifiedDocuments = rowGroup.Count()
};
And then use your 2 queries sorted by Name.
Related
I am trying to query two tables and need to pull related records from both the tables. I am using enityframeworkcore 3 One is system versioned table and the other is history table. My resultset is containing data only from history table and not system-versioned table. Could somebody tell me what is wrong with my statement . I am ensured that the personid in the systemversion table matches the history table.
Query
var personNotes = (from pn in _context.PersonNotes
join pnh in _context.PersonNotesHistory on pn.PersonId equals pnh.PersonId
select pn);
return personNotes;
You need to specify the column names you want to return in the result:
var personNotes = (from pn in _context.PersonNotes
join pnh in _context.PersonNotesHistory on pn.PersonId equals pnh.PersonId
select new {
data1 = pn.column1,
data2 = pn.column2,
data3 = pn.column3,
data4 = pnh.column1,
data5 = pnh.column2,
data6 = pnh.column3,
}).ToList();
return personNotes;
Just change the column1, column2, column3 with column names you want to retrieve from the database.
As an alternative to the first answer you may use this syntax:
var personNotes = _context.PersonNotes
.Join(_context.PersonNotesHistory, pn => pn.PersonId, pnh => pnh.PersonId, (pn, pnh) => new
{
pn.Note,
pn.AuthorID,
pn.CreatedBy,
pnh.Note,
pnh.AuthorID,
pnh.CreatedBy
})
.ToList();
Very new with LINQ here.
I have the following data in my table (TableA):
ID Name SubmissionNo
1 Jim A-1
2 Andy A-2
3 Rick A-2
4 Mary A-3
5 Zim A-4
6 Loren A-1
I then need to create a query which will allow me to get from that table, those records which have duplicate submission numbers.
Here's my solution so far (Context is the database context):
var duplicates = (from tbl in Context.TableA.AsNoTracking()
group tbl by tbl.SubmissionNo into grp
select new { count = grp.Count(), submissionNo = grp.Key})
.Where(x => x.count > 1)
.OrderBy(y => y.submissionNo).ToList();
The variable duplicates then contains the record:
count submissionNo
2 A-1
2 A-2
I then write the main query which will allow me to get all the records from TableA which has duplicate submissionNo
var myList = (from tbl in Context.TableA.AsNoTracking()
join dup in duplicates on tbl.SubmissionNo equals dup.submissionNo
select new
{
ID = tbl.ID,
Name = tbl.Name,
SubmissionNo = tbl.SubmissionNo
})
.ToList();
I am then getting an error for the myList query with
Unable to create a constant value of type 'Anonymous Type'. Only primitive types or enumeration types are supported in this context.
I think there must be a better way to do this as from the TableA above, I practically want the following results:
ID Name SubmissionNo
1 Jim A-1
2 Andy A-2
3 Rick A-2
6 Loren A-1
Your first query, slightly modified, has all information you need:
var myList = from tbl in Context.TableA.AsNoTracking()
group tbl by tbl.SubmissionNo into grp
where grp.Count() > 1
from item in grp
select new
{
count = grp.Count(),
submissionNo = grp.Key,
item.Name,
);
The pattern group into grp - from item in grp is a commonly used query pattern to group items and then flatten the group again, while keeping in touch with the group data (like Count() and Key).
Now you don't need the join anymore and the exception doesn't occur. By the way, the exception tells you that EF can only handle joins with collections of primitive types (int etc.), because it has to translate the whole expression into SQL. There's simply no translation for rich objects like TableA.
By the way, the query can be improved by removing the repeated Count():
var myList = from tbl in Context.TableA.AsNoTracking()
group tbl by tbl.SubmissionNo into grp
let count = grp.Count()
where count > 1
from item in grp
select new
{
count = count,
submissionNo = grp.Key,
item.Name,
);
This will generate a more efficient SQL statement containing one COUNT instead of two.
Since Entity Framework does not support joining in-memory collections of objects with database collections, a common workaround for this is to filter using Contains.
First, you need to get the IDs to filter on:
var duplicates = (from tbl in Context.TableA.AsNoTracking()
group tbl by tbl.SubmissionNo into grp
select new { count = grp.Count(), submissionNo = grp.Key})
.Where(x => x.count > 1)
.OrderBy(y => y.submissionNo)
.ToList();
var duplicateIds = duplicates.Select(x => x.submissionNo).ToList();
And then change your query to perform a WHERE...IN instead of a JOIN:
var myList = (from tbl in Context.TableA.AsNoTracking()
where duplicateIDs.Contains(tbl.SubmissionNo)
select new
{
ID = tbl.ID,
Name = tbl.Name,
SubmissionNo = tbl.SubmissionNo
})
.ToList();
Let's say I have a table that holds shipping history. I'd like to write a query that counts the amount of shipments per user and gets the shipping name from the most recent entry in the table for that user.
Table structure for simplicity:
ShipmentID
MemberID
ShippingName
ShippingDate
How do I write a LINQ C# query to do this?
It sounds like might want something like:
var query = from shipment in context.ShippingHistory
group shipment by shipment.MemberID into g
select new { Count = g.Count(),
MemberID = g.Key,
MostRecentName = g.OrderByDescending(x => x.ShipmentDate)
.First()
.ShipmentName };
Not really a LINQ answer, but personally, I'd be dropping to SQL for that, to make sure it isn't doing any N+1 etc; for example:
select s1.MemberID, COUNT(1) as [Count],
(select top 1 ShippingName from Shipping s2 where s2.MemberID = s1.MemberID
order by s2.ShippingDate desc) as [LastShippingName]
from Shipping s1
group by s1.MemberID
You can probably do LINQ something like (untested):
var qry = from row in data
group row by row.MemberId into grp
select new {
MemberId = grp.Key,
Count = grp.Count(),
LastShippingName =
grp.OrderByDescending(x => x.ShippingDate).First().ShippingName
};
I am using a linq query to obtain a table of customers with their total money amount for each monetary unit exist in my database(this one is ok.)
when show the result of my query with Microsoft Report Viewer the result is like Table 1 but what i want is Table 2, only the customer name like "A" and a cell with all the monetory unit records > 0.
Is there any way you can suggest?
This is my code which produces Table 1:
var query = from kur in kurToplamlist
join cariBilg in db.TBLP1CARIs
on kur.CariIdGetSet equals cariBilg.ID
select new
{
cariBilg.ID,//customerid
EUROBAKIYE = cariBilg.HESAPADI,
cariBilg.K_FIRMAADI,//other column names
cariBilg.K_YETKILIADI,//other column names
cariBilg.K_FIRMATELEFON,//other column names
cariBilg.K_YETKILITELEFON,//other column names
AUDBAKIYE = cariBilg.B_CEPTELEFON,//other column names
MonetaryUnit = String.Concat(kur.KurToplamMiktarGetSet.ToString(), kur.DovizTuruGetSet.ToString()),//concatenates "100" and "TL/USD etc."
};
What i want is to obtain Table 2 in the image
Thank you in advance.
Table image
var query = from kur in kurToplamlist
where kur.KurToplamMiktarGetSet > 0
join cariBilg in db.TBLP1CARIs
on kur.CariIdGetSet equals cariBilg.ID
select new
{
cariBilg.ID,
EUROBAKIYE = cariBilg.HESAPADI,
cariBilg.K_FIRMAADI,
cariBilg.K_YETKILIADI,
cariBilg.K_FIRMATELEFON,
cariBilg.K_YETKILITELEFON,
AUDBAKIYE = cariBilg.B_CEPTELEFON,
TLBAKIYE = String.Concat(kur.KurToplamMiktarGetSet.ToString(), kur.DovizTuruGetSet.ToString()),
};
var dfg = from qre in query
select qre.TLBAKIYE;
var aq = (from qw in query
select new {
qw.ID,
EUROBAKIYE = qw.EUROBAKIYE,
qw.K_FIRMAADI,
qw.K_YETKILIADI,
qw.K_FIRMATELEFON,
qw.K_YETKILITELEFON,
AUDBAKIYE = qw.AUDBAKIYE,
TLBAKIYE = String.Join(",", (from qre in query
where qre.ID == qw.ID
select qre.TLBAKIYE).Distinct())
}).Distinct();
return aq;
This is my answer.
How can I order the results from "group ... by... into..." statement in linq?
For instance:
var queryResult = from records in container.tableWhatever
where records.Time >= DateTime.Today
group records by tableWhatever.tableHeader.UserId into userRecords
select new { UserID = userRecords.Key, Records = userRecords };
The query returns records in table "contain.tableWhatever" grouped by "UserId". I want the returned results within each group ordered by time decending. How can I do that?
More specific, assume the above query return only one group like the following:
{UserID = 1, Records= {name1 5/3/2010_7:10pm;
name2 5/3/2010_8:10pm;
name3 5/3/2010_9:10pm} }
After insert the orderby statement in the above query, the returned results should be like this:
{UserID = 1, Records= {name3 5/3/2010_9:10pm;
name2 5/3/2010_8:10pm;
name1 5/3/2010_7:10pm} }
Thanks for help!
Simply use the OrderByDescending extension to order the records in the anonymous type.
var queryResult = from records in container.tableWhatever
where records.Time >= DateTime.Today
group records by tableWhatever.tableHeader.UserId into userRecords
select new
{
UserID = userRecords.Key,
Records = userRecords.OrderByDescending( u => u.Time )
};
could you do:
var queryResult = from records in container.tableWhatever
where records.Time >= DateTime.Today
group records by tableWhatever.tableHeader.UserId into userRecords
select new { UserID = userRecords.Key, Records = userRecords.OrderByDescending(r=>r.Time) };