I have two classes. Bills and Transactions. One bill is made up of many transactions. I am able to display bills and I am able to display transactions on their own. But I would like to display the last 10 bills (this part is done), but each bill should show all its transactions.
This part of the code is used to get all transactions of a bill
{ Bill bill = (Bill)Bills.Instance.GetBillsByCustomerID(id);
//get all transactions of bill
var transactions = from t in this._entities.Transactions
where t.Bill.bID == bill.bID
select new
{
t.Product.pName, t.tQty, t.tUnitPrice, t.Bill.bTotal, t.Bill.bTimestamp, t.Bill.bCustomerIDF
};
}
Now I would like that the following query below, would have some sort of nested query where all transactions OF EACH BILL are obtained: (at the moment, this only displays 10 bills - and no transactions
{
//returns top 10
var bills = (from b in this._entities.Bills
where b.bCustomerIDF == id
orderby b.bTimestamp descending
select new { b.bTotal, b.bTimestamp, b.Customer.cName}).Take(10);
return bills;
}
Can you please guide me to a simple solution? Thank you
I believe you want a join with an into
var bills = (from b in this._entities.Bills
join t in this._entities.Transactions on t.Bill.bID equals b.bID into tg
where b.bCustomerIDF == id
orderby b.bTimestamp descending
select new
{
b.bTotal,
b.bTimestamp,
b.Customer.cName,
Transactions = tg
}
).Take(10);
return bills;
I would have thought that you should just be able to add something like the following into your select:
transactions.Where(x=>x.Bill.bID == b.bID)`
That having been said I do also think it sounds like your object model is wrong. I'd have expected a Bill to have a collection of Transactions that are on that Bill.
Related
I want to change code below to be sql translateable because now i get exception.
Basicallly i want list of customers from certain localisation and there could be more than one customer with the same CustomerNumber so i want to take the one that was most recently added.
In other words - distinct list of customers from localisation where "distinct algorithm" works by taking the most recently added customer if there is conflict.
The code below works only if it is client side. I could move Group By and Select after ToListAsync but i want to avoid taking unnecessary data from database (there is include which includes list that is pretty big for every customer).
var someData = await DbContext.Set<Customer>()
.Where(o => o.Metadata.Localisation == localisation)
.Include(nameof(Customer.SomeLongList))
.GroupBy(x => x.CustomerNumber)
.Select(gr => gr.OrderByDescending(x => x.Metadata.DateAdded).FirstOrDefault())
.ToListAsync();
Short answer:
No way. GroupBy has limitation: after grouping only Key and Aggregation result can be selected. And you are trying to select SomeLongList and full entity Customer.
Best answer:
It can be done by the SQL and ROW_NUMBER Window function but without SomeLongList
Workaround:
It is because it is not effective
var groupingQuery =
from c in DbContext.Set<Customer>()
group c by new { c.CustomerNumber } into g
select new
{
g.Key.CustomerNumber,
DateAdded = g.Max(x => x.DateAdded)
};
var query =
from c in DbContext.Set<Customer>().Include(x => x.SomeLongList)
join g in groupingQuery on new { c.CustomerNumber, c.DateAdded } equals
new { g.CustomerNumber, g.DateAdded }
select c;
var result = await query.ToListAsync();
I have two entities who are N:N - related with each other. With an example I'll show you what I mean :
I have a Session (ave_Session) and there we can put "Trainers"
(ave_trainer) on each Session
I'm tryting to get a list of al the
"Trainers" for a particular Session
They are related to each other in
N:N (relationship name : ave_ave_session_ave_trainer)
I work in VS2010 and with C# => I'm trying to get the data through LINQ
I recently just started with LINQ, so maybe you guys can help me out on this one. The following I've tried and i gave me an "AttributeFrom and AttributeTo must be either both specified or both ommited. You can not pass only one or the other. AttributeFrom: , AttributeTo: ave_trainerid"-error :
var formatteurs = (from f in ORGContext.CreateQuery<ave_trainer>()
join s in ORGContext.CreateQuery<ave_ave_session_ave_trainer>() on f.Id equals s.ave_trainerid.Value
join c in ORGContext.CreateQuery<ave_session>() on s.ave_sessionid.Value equals c.Id
where c.Id == item.Id
select f).ToList();
The item.id is the Id of the session. Thx in advance if you can help me out!
From the MSDN page:
// List the contacts in the Softball team marketing list.
System.Console.WriteLine("List all contacts in Softball Team:");
var members = from c in crm.contacts
join mlm in crm.listmembers on c.contactid equals mlm.entityid
join ml in crm.lists on mlm.listid equals ml.listid
where ml.listname == "Softball Team"
select c;
foreach (var c in members)
{
System.Console.WriteLine(c.fullname + " " + c.emailaddress1);
}
It seems a little backwards the way you have it written now (assuming I'm parsing it correctly).
What you'd normally do is put your 'starting thing' first and then go through the mapping to get to the ones you want. I don't have any CRM 2011 experience, so hopefully I didn't mess this up too much. :)
Also, I'm not a fan of single-character names, so I took the liberty of using longer names :)
var formatteurs = (
// first get the session we're interested in
from session in ORGContext.CreateQuery<ave_session>()
where session.Id == item.Id
// now get the mapping rows that are related to it
join mapping in ORGContext.CreateQuery<ave_ave_session_ave_trainer>()
on session.Id equals s.ave_sessionid.Value
// now get from the mapping rows to the actual trainers
join trainer in ORGContext.CreateQuery<ave_trainer>()
on mapping.ave_trainerid.Value equals trainer.Id
select trainer
).ToList();
I have 3 tables: DiaryPosts, DiaryImpressions, Impressions.
Impressions is a small list with some fields: 'like', 'dislike', 'agree', 'disagree'. The user can vote according to what he thinks about the post.
DiaryImpressions is the table that handles the relationship between the posts and the users who vote.
My problem is, I have to count results of each impression vote for each post, so maybe for one post 13 users voted for like, 2 for dislike, 34 agree and 1 disagree.
I have no idea how to perform the query in some way I can get this specific count results for each impression.
Can anyone help me with that?
You can do this via the GroupBy method. It allows you to automatically "group" the elements based on the impression, and count the results per group.
var post(from c in posts selec c)
string post1like;
string post2dislike;
string postagree3;
string postdisagree3;
foreach (var item in posts)
{
var ipressionslike=(from c in imressions where impressioid=item.id where c.impressionID='LIKE' select c.userID).Tolist()
var ipressionsdislike=(from c in imressions where impressioid=item.id where c.impressionID='disLIKE' select c.userID).Tolist()
var ipressionslike=(from c in imressions where impressioid=item.id where c.impressionID='LIKE' select c.userID).Tolist()
var ipressionsagree=(from c in imressions where impressioid=item.id where c.impressionID='disLIKE' select c.userID).Tolist()
post1like+=item.id+""+ipressionsdislike.count;
post2dislike+=item.id+""+ipressionslike.count;
postagree3+=item.id+""+ipressionsagree.count;
}
it should count the impressions for each post and count the amount of users that like or dislike so if you have 30 people dislike for each post it should get them I cannot see your table structure but I hope it will help or point you somewhere
I have to guess but here is what I think the SQL would look like:
SELECT I.Name, COUNT(I.Name)
FROM DairyPosts P
JOIN DairyImpressions DI ON P.ID=DI.DairyID
JOIN Impressions I ON DI.ImpressionsID = I.ID
And what the linq would look like:
List<Dairy> dairyposts = GetDairyPosts();
var impressionCounts =
from p in dairyposts
group p by p.ImpressionName into g
select new { Type = g.Key, ImpressionCount = g.Count() };
Of course I have to assume your list is created a certain way, if you can post how your list is actually created that would help. (As I said in the comments)
I'm really, really struggling with what should otherwise be a straightforward query in anything other than LINQ (for example SQL!)
I have two entities:
Product
ProductApprover
The Product entity has a one to many relationship on the ProductApprover entity, e.g:
Product.ProductApprovers gives me all ProductApprover entities relating to the Product.
Getting a Product and associated ProductApprover data is simple enough when querying by my ProductID column on my Product entity as the ProductApprover data associated is bundled into the result automatically, but my problem comes when I want to alter my query by querying data WITHIN my associated ProductApprover entities. I have tried all sorts with use of the 'Where', 'Contains' and 'Any', functions, etc, to perform a subquery, but cannot seem to get the result I want.
The query I want to perform is:
SELECT * FROM Product p
INNER JOIN ProductApprover pa ON p.ProductId = pa.ProductId
WHERE p.ProductId = #id AND pa.Version = #version
Can anybody help me out please? Thank you kindly in advance.
Try this (I guess this is a LINQ interpretation of your SQL query):
int id = 123;
int version = 555;
var results = from p in context.Products
join pa in context.ProductApprovers
on p.ProductId = pa.ProductId
where p.ProductId equals id && pa.Version equals version
select new { Product = p, Approver = pa };
I suspect you want something like this:
var query = from product in db.Products
where product.ProductId == productId
select new {
Product = product,
Approvers = product.Approvers.Where(pa => pa.Version == version)
};
If that doesn't do what you want, could you explain where it falls down?
I am trying to translate this into Linq and cannot figure it out:
SELECT
CustomerOrder.ShipState, MONTH(OrderFulfillment.OrderDate) AS Mnth,
YEAR(OrderFulfillment.OrderDate) AS Yer,
SUM(OrderFulfillment.Tax) AS TotalTax
FROM
OrderFulfillment INNER JOIN
CustomerOrder ONOrderFulfillment.OrderID =CustomerOrder.OrderID
WHERE
(OrderFulfillment.Tax > 0)
GROUP BY
CustomerOrder.ShipState, MONTH(OrderFulfillment.OrderDate),
YEAR(OrderFulfillment.OrderDate)
ORDER BY
YEAR(OrderFulfillment.OrderDate) DESC, CustomerOrder.ShipState,
MONTH(OrderFulfillment.OrderDate) DESC
I have Linqpad and have gone through a bunch of the examples but cannot figure this out.
I think you want to do something like this:
from c in CustomerOrder
join o in OrderFulfillment on c.OrderId equals o.OrderId
where
o.Tax > 0
group o by
new { c.ShipState, Mnth = of.OrderDate.Month, Yer = of.OrderDate.Year }
into g
orderby
g.Key.Yer descending, g.ShipState, g.Key.Mnth descending
select
new { g.Key.ShipState, g.Key.Mnth, g.Key.Yer,
TotalTax = g.Sum(i => i.Tax) };
I haven't tried to compile it, but I think this is something along the lines of what you want.
The idea is that first you perform your join to link the customers and orders. Then apply your filter condition.
At that point, you want to get all the orders that have a particular group, so the group operator is applied.
Finally, order the results, then select out all info from the keys for each group, and sum up the tax in each of the group.
First of all, it would be nice to know what exactly you can't figure out. If you're completely lost and don't know where to begin then you need to google around for linq joining and grouping.
Here's something I did recently that may (possibly) point you in the right direction:
// This groups items by category and lists all category ids and names
from ct in Categories
join cst in Category_Subtypes
on ct.Category_Id equals cst.Category_Id
join st in Subtypes
on cst.Subtype_Id equals st.Subtype_Id
where
st.Type_Id == new Guid(id)
group ct by new { ct.Category_Id, ct.Display_Text } into ctg
select new
{
Id = ctg.Key.Category_Id,
Name = ctg.Key.Display_Text
}