get list of decision for a specific meetingtitle using linq asp.net - sql

I have a database table. What I want is to get data using group by clause as I have used in below code.
Note that Decision is another table. now I want that all the decisions related to a specific Meeting Title should be shown in list.like
meetingtitle1=decision1,decison2,decison3
meetingtitle2=decision1,decison2
but below code returns only one decisiontitle.
public List<NewMeetings> GetAllMeetings()
{
var xyz = (from m in DB.MeetingAgenda
//join mp in Meeting on m.MeetingId equals mp.MeetingId
//where m.MeetingId == 2
group m by new { m.Meeting.MeetingTitle } into grp
select new NewMeetings
{
// meetingid = grp.Key.MeetingId,
meetingtitle = grp.Key.MeetingTitle,
decision = grp.Select(x => x.Decision.DecisionTitle).FirstOrDefault(),
total = grp.Count()
}).ToList();
List<NewMeetings> list = xyz.ToList();
return list;
}
public class NewMeetings
{
public int meetingid;
public string meetingtitle;
public string decision;
public int total;
}
Can somebody please tell me how to return a list of decisions to a specific Meetingtitle?

You are doing a FirstOrDefault on the list of decisions which obviously means you are only getting a single value. Instead you can join them all together into one longer string (separated by commas as you indicated in the question) by changing this line:
decision = grp.Select(x => x.Decision.DecisionTitle).FirstOrDefault(),
To this:
decision = string.Join(",", grp.Select(x => x.Decision.DecisionTitle)),
However, as the string.Join is not recognised by Linq to Entities, you need to do the string.Join after the data has been retrieved (i.e. after the ToList):
var xyz = (from m in DB.MeetingAgenda
group m by new { m.Meeting.MeetingTitle } into grp
select new
{
meetingtitle = grp.Key.MeetingTitle,
decisions = grp.Select(x => x.Decision.DecisionTitle),
total = grp.Count()
})
.ToList()
.Select(m => new NewMeetings
{
meetingtitle = m.meetingtitle,
decision = string.Join(",", m.decisions),
total = m.total
});

Related

Raven DB filter on subset of array items and sort on the cheapest of the filter results items

Assuming i have an parent class that I filter on various properties, one of which is a property that is an array of items .
Now say that i want to only return the parent item if my array of items as above a min value and below a max value ...that's fine i can work that bit out;
What if i then want to then sort on the filtered result set of those items
I made a c# fiddle example to show what im trying to achieve :
https://dotnetfiddle.net/mV4d28
(note that foo2 is returned first even though foo1 has items in its array that are less that those in foo2)
As i need to do this using a index i need the index to be able to compute the order by based on the filter criteria used in my query.
I know elasticsearch has an inner hits function that dose this and mongo has pipelines which also dose this so im sure Raven must have a way of doing this too ?
I was hoping using just index and a transform with prams i could achieve this so I tried it:
my index and transform look like this
public class familyTransfrom : AbstractTransformerCreationTask<ParentItem>
{
public class Result : ParentItem{
public double[] ChildItemValuesFiltered { get; set; }
}
public familyTransfrom(){
TransformResults = parents => from parent in parents
let filterMinValue = Convert.ToDouble(ParameterOrDefault("FilterMinValue", Convert.ToDouble(0)).Value<double>())
let filterMaxValue = Convert.ToDouble(ParameterOrDefault("FilterMaxValue", Convert.ToDouble(9999)).Value<double>())
select new Result{
ParentItemId = parent.ParentItemId,
ParentItemName = parent.ParentItemName,
ParentItemValue = parent.ParentItemValue,
//ChildItemValuesFiltered = parent.ChildItems.Where(p => p.ChildItemValues.Any(y => Convert.ToDouble(y) >= Convert.ToDouble(filterMinValue) && Convert.ToDouble(y) <= Convert.ToDouble(filterMaxValue))).SelectMany(t => t.ChildItemValues).ToArray<double>(),
ChildItemValuesFiltered = parent.ChildItems.SelectMany(p => p.ChildItemValues.Where(y => Convert.ToDouble(y) >= Convert.ToDouble(filterMinValue) && Convert.ToDouble(y) <= Convert.ToDouble(filterMaxValue))).ToArray<double>(),
ChildItems = Recurse(parent, x => x.ChildItems).Select(y => y).ToArray()
};
}
}
public class familyIndex : AbstractIndexCreationTask<ParentItem>{
public class Result : ParentItem {
public double[] ChildItemValues { get; set; }
}
public familyIndex(){
Map = parents => from parent in parents
select new Result{
ParentItemId = parent.ParentItemId,
ParentItemName = parent.ParentItemName,
ParentItemValue = parent.ParentItemValue,
ChildItemValues = parent.ChildItems.SelectMany(p => p.ChildItemValues.Select(y => y)).ToArray(),
ChildItems = Recurse(parent, x => x.ChildItems).Select(y => y).ToArray()
};
Index("ParentItemId", FieldIndexing.Analyzed);
Index("ParentItemName", FieldIndexing.Analyzed);
Index("ParentItemValue", FieldIndexing.Analyzed);
Index("ChildItemValues", FieldIndexing.Analyzed);
Index("ChildItems", FieldIndexing.Analyzed);
}
}
my query is as follows , (this is using the live raven playground so this should just work out of the box it you want to use it)
using (IDocumentStore store = new DocumentStore { Url = "http://live-test.ravendb.net/", DefaultDatabase = "altha" })
{
store.Initialize();
using (IDocumentSession session = store.OpenSession())
{
if(1 == 2){
//foreach (ParentItem element in data.OfType<ParentItem>()) {
// session.Store((ParentItem)element);
// session.SaveChanges();
//}
new familyIndex().Execute(store);
new familyTransfrom().Execute(store);
}else{
double filterMinValue = 3.0;
double filterMaxValue = 4.0;
var results = session
.Advanced
.DocumentQuery<familyIndex.Result,familyIndex>()
.WhereBetweenOrEqual("ChildItemValues", filterMinValue, filterMaxValue)
.SetResultTransformer<familyTransfrom, familyTransfrom.Result>()
.SetTransformerParameters(new Dictionary<string, RavenJToken> {
{ "FilterMinValue", filterMinValue },
{ "FilterMaxValue", filterMaxValue } })
.OrderBy("ChildItemValues")
.OfType<ParentItem>().ToList();
results.Dump();
}}
}
What i found was i cant use "ChildItemValuesFiltered" from the transform result as its not index. So unless i can order by the result of a transform ? i couldn't get this to work as although it filters it dosnt order correctly.
Is there another to achieve what i want using projections or intersection or rank or reduce try method ?
I was thinking if i had to perhaps i could use https://ravendb.net/docs/article-page/3.5/csharp/indexes/querying/sorting#custom-sorting
and do something like this:
public class SortByNumberOfCharactersFromEnd : IndexEntriesToComparablesGenerator
{
private readonly double filterMinValue;
private readonly double filterMinValue;
public SortByNumberOfCharactersFromEnd(IndexQuery indexQuery)
: base(indexQuery)
{
filterMinValue = IndexQuery.TransformerParameters["FilterMinValue"].Value<double>(); // using transformer parameters to pass the length explicitly
filterMaxValue = IndexQuery.TransformerParameters["FilterMaxValue"].Value<double>();
}
public override IComparable Generate(IndexReader reader, int doc)
{
var document = reader.Document(doc);
double[] childItemValues = (double[])document.GetValues("ChildItemValuesFiltered").Select(double.Parse).ToArray(); // this field is stored in index
return childItemValues.Where(x => x >= min && x <= max).Min();
}
}
then do a where filter and order by clause using index and transform passing in the same prams that i use in the where filter . however im not sure if this would work ?
More importantly im not sure how i go about getting the sort dll into the plugins ie what name space should the class go under, what name spaces dose it need to import, what assembly name dose it need to use etc
According to https://ravendb.net/docs/article-page/3.5/csharp/server/plugins/what-are-plugins i just need to drop the dll in and raven will this this up , however i cant seem to find what name space i need to reference for IndexEntriesToComparablesGenerator ?
im using linqpad 5 to test my stuff ...so in order to use the custom order i have to reference the class
any tips or advice or how to guild/examples welcome
so it didn't occur to me that i could do the filtering in the transform
TransformResults = parents => from parent in parents
let filterMinValue = Convert.ToDouble(ParameterOrDefault("FilterMinValue", Convert.ToDouble(0)).Value<double>())
let filterMaxValue = Convert.ToDouble(ParameterOrDefault("FilterMaxValue", Convert.ToDouble(9999)).Value<double>())
select new {
ParentItemId = parent.ParentItemId,
ParentItemName = parent.ParentItemName,
ParentItemValue = parent.ParentItemValue,
//ChildItemValuesFiltered = parent.ChildItems.Where(p => p.ChildItemValues.Any(y => Convert.ToDouble(y) >= Convert.ToDouble(filterMinValue) && Convert.ToDouble(y) <= Convert.ToDouble(filterMaxValue))).SelectMany(t => t.ChildItemValues).ToArray<double>(),
ChildItemValuesFiltered = parent.ChildItems.SelectMany(p => p.ChildItemValues.Where(y => Convert.ToDouble(y) >= Convert.ToDouble(filterMinValue) && Convert.ToDouble(y) <= Convert.ToDouble(filterMaxValue))).ToArray<double>(),
ChildItems = Recurse(parent, x => x.ChildItems).Select(y => y).ToArray()
} into r
where r.ChildItemValuesFiltered.Length > 0
orderby r.ChildItemValuesFiltered.Min()
select r;
This gives me what i wanted, here are the sample query:
http://live-test.ravendb.net/databases/altha/indexes/familyIndex?start=0&pageSize=25&resultsTransformer=familyTransfrom&tp-FilterMinValue=3&tp-FilterMaxValue=4
i cant take credit for this as guys at raven helped me but sharing the knowledge for others

Remove items from a collection in entity framework

I have a function as below :
IEnumerable<Group> GetAllChildren(int parentID)
{
using (Entities db = new Entities())
{
var result = (from x in db.Groups
where x.ParentID == parentID
select x).ToList();
foreach (Group child in result.ToList())
{
result.AddRange(GetAllChildren(child.GroupID));
}
return result;
}
}
In the above function if I pass a group name I get all the children at all levels.
It works as expected.
Now my query looks like something like :
GroupNamesWithCorrespondingEffects
= new ObservableCollection<GroupNameWithCorrespondingEffect>
(from g in db.Groups
select new GroupNameWithCorrespondingEffect
{
GroupID = g.GroupID,
GroupName = g.GroupName,
CorrespondingEffect = g.Master_Effects.Effect
}
);
The above query will give me all the groups.
Now I want to remove all the groups from GroupNamesWithCorrespondingEffects that are children of a group with id == 25.
I have tried .Remove(GetAllChildren(25)) in 2nd query. but I get following error.
Collection.Remove(GroupNameWithCorrespondingEffect) has some invalid arguments.
hope this help you:
var childs = GetAllChildren(25).ToList();
var childIDList = childs.select(u => u.GroupID).ToList();
GroupNamesWithCorrespondingEffects = GroupNamesWithCorrespondingEffects
.Where(u => !childIDList.Contains(u.GroupID)).ToList();

Linq to sql How to select elements from a list

I have two classes:
public class Artikel
{
int id{get;set;};
string name{get;set;};
}
public class NewArtikel
{
int id{get;set;};
List<Artikel> artikels{get;set;};
}
Now, I have a list of the second class
List<NewArtikel> myList = new List<NewArtikel>()
Is there are any posibility in LINQ to SQL to select all elements from myList with the needed Artikel.name
Yes
var allRequiredArtikels = myList.SelectMany(n => n.artikels)
.Where(a => a.name == "requiredName");
The SelectMany flattens all Artikels from all the NewArtikel elements, then the Where filters them by name.
Okay so, if you want the NewArtikels that have an Artikel with the required name you could do.
var newArtikels = myList.Where(n => n.artikels
.Any(a => a.name == "requiredName"));
List<NewArtikel> myFinalList = (from artikel in myList.artikels where artikel.name = "requiredName"
select new NewArtikel(){
Id= artikel.Id
}).ToList();

How can I make a nested projection in a Linq query when using the group by clause?

I'm trying to work with grouped data coming back from SQL.
The method I'm writing is to provide the data for a "Case Status Overview" screen.
It must produce a nested XML document.
Now, I could do it the easy way, but I'm trying to learn whether it's possible to use the linq "group by" statement and then to project the data already nested. (the easy way would be just to pull back the data in a tabular fashion from the database and then for-loop through it forming the Xml document for output)
Here is the data hierarchy:
Every Case has a DebtType and every DebtType has a Client.
Here is the SQL that retrieves the data:
SELECT ClientNames.ClientID ,
ClientNames.ClientCode ,
ClientNames.ClientName ,
DebtTypes.DebtTypeID ,
DebtTypes.DebtTypeShortDesc ,
DebtTypes.DebtTypeLongDesc ,
Cases.CurrentStateCode ,
SUM(1 - CAST(Cases.CaseClosed AS INT)) AS OpenCaseCount ,
SUM(CAST(Cases.CaseClosed AS INT)) AS ClosedCaseCount ,
SUM(CAST(Cases.CaseOnHold AS INT)) AS OnHoldCaseCount ,
SUM(CAST(Cases.CaseReferred AS INT)) AS ReferredCaseCount ,
COUNT(Cases.CaseID) AS TotalCaseCount ,
SUM(Cases.CaseTotalPaid) AS TotalAmountPaid ,
SUM(Cases.CaseCurrentOutstandingAmount) AS TotalAmountOutstanding,
SUM(Cases.CaseTotalDebtWrittenOff) AS TotalAmountWrittenOff ,
SUM(Cases.CaseTotalDebtCancelled) AS TotalAmountCancelled
FROM ClientNames
INNER JOIN ClientDebtTypes
ON ClientNames.ClientID = ClientDebtTypes.ClientID
INNER JOIN DebtTypes
ON ClientDebtTypes.DebtTypeID = DebtTypes.DebtTypeID
INNER JOIN Cases
ON ClientDebtTypes.ClientDebtTypeID = Cases.CaseClientDebtTypeID
GROUP BY ClientNames.ClientID ,
ClientNames.ClientCode ,
ClientNames.ClientName ,
DebtTypes.DebtTypeID ,
DebtTypes.DebtTypeShortDesc,
DebtTypes.DebtTypeLongDesc ,
Cases.CurrentStateCode
ORDER BY ClientNames.ClientID,
DebtTypes.DebtTypeID,
CurrentStateCode
Using Linqer it converts it to:
from clientnames in db.ClientNames
join clientdebttypes in db.ClientDebtTypes on clientnames.ClientID equals clientdebttypes.ClientID
join debttypes in db.DebtTypes on clientdebttypes.DebtTypeID equals debttypes.DebtTypeID
join cases in db.Cases on new { ClientDebtTypeID = clientdebttypes.ClientDebtTypeID } equals new { ClientDebtTypeID = cases.CaseClientDebtTypeID }
group new {clientnames, debttypes, cases} by new {
clientnames.ClientID,
clientnames.ClientCode,
clientnames.ClientName1,
debttypes.DebtTypeID,
debttypes.DebtTypeShortDesc,
debttypes.DebtTypeLongDesc,
cases.CurrentStateCode
} into g
orderby
g.Key.ClientID,
g.Key.DebtTypeID,
g.Key.CurrentStateCode
select new {
ClientID = (System.Int32?)g.Key.ClientID,
g.Key.ClientCode,
g.Key.ClientName1,
DebtTypeID = (System.Int32?)g.Key.DebtTypeID,
g.Key.DebtTypeShortDesc,
g.Key.DebtTypeLongDesc,
g.Key.CurrentStateCode,
OpenCaseCount = (System.Int64?)g.Sum(p => 1 - Convert.ToInt32(p.cases.CaseClosed)),
ClosedCaseCount = (Int32?)g.Sum(p => Convert.ToInt32(p.cases.CaseClosed)),
OnHoldCaseCount = (Int32?)g.Sum(p => Convert.ToInt32(p.cases.CaseOnHold)),
ReferredCaseCount = (Int32?)g.Sum(p => Convert.ToInt32(p.cases.CaseReferred)),
TotalCaseCount = (Int64?)g.Count(p => p.cases.CaseID != null),
TotalAmountPaid = (System.Decimal?)g.Sum(p => p.cases.CaseTotalPaid),
TotalAmountOutstanding = (System.Decimal?)g.Sum(p => p.cases.CaseCurrentOutstandingAmount),
TotalAmountWrittenOff = (System.Decimal?)g.Sum(p => p.cases.CaseTotalDebtWrittenOff),
TotalAmountCancelled = (System.Decimal?)g.Sum(p => p.cases.CaseTotalDebtCancelled)
}
Now as I mentioned, I could stop there and right a for loop to create the Xml data.
But I'm trying to create a nested group (IGrouping<ClientName,IGrouping<DebtType,SummaryClass>>)
and then project the data in a nested format.
Now we're using LinqToXsd to create strong type wrappers for out Xml documents, but essentially all this means is that out output type is:
private class ClientSummary
{
public string ClientName { get; set; }
public IList<DebtTypeSummary> DebtTypes { get; set; }
}
private class DebtTypeSummary
{
public string DebtType { get; set; }
public IList<StateCodeSummary> StateCodes { get; set; }
}
private class StateCodeSummary
{
public string StateCode { get; set; }
public int TotalCount { get; set; }
public decimal TotalAmountPaid { get; set; }
//etc
//etc
//etc
}
Now I got as far as writing the following Linq:
var grouping = from cases in db.Cases
join clientdebttypes in db.ClientDebtTypes on cases.CaseClientDebtTypeID equals clientdebttypes.ClientID
join debttypes in db.DebtTypes on clientdebttypes.DebtTypeID equals debttypes.DebtTypeID
group cases by new ClientDebtTypePair() { ClientDebtType = clientdebttypes, DebtType = debttypes } into casesByClientDebtTypes
join clientnames in db.ClientNames on casesByClientDebtTypes.Key.ClientDebtType.ClientName equals clientnames
group casesByClientDebtTypes by clientnames;
var projected = from casesByClientDebtTypes in grouping
let client = casesByClientDebtTypes.Key
select new LoadCaseStatusOverviewScreenOutput.ClientsLocalType()
{
Client = new Client()
{
ClientID = client.ClientID,
DisplayName = client.ClientName1,
},
DebtTypes = from cases in casesByClientDebtTypes
let debttype = cases.Key.DebtType
select new LoadCaseStatusOverviewScreenOutput.ClientsLocalType.DebtTypesLocalType()
{
DebtType = new DebtType()
{
DebtTypeID = debttype.DebtTypeID,
Description = debttype.DebtTypeLongDesc,
DisplayName = debttype.DebtTypeShortDesc,
},
StatesCodes = from cases2 in cases
select new LoadCaseStatusOverviewScreenOutput.ClientsLocalType.DebtTypesLocalType.StatesCodesLocalType()
{
ClosedCasesCount = cases2.Sum(p => Convert.ToInt32(p.cases.CaseClosed))
which joins and groups the database tables and then tries to project the result a ClientSummary (the class names are different but that's because the above is a simplified view of the output classes). I fail completely when I've drilled all the way down to the Cases table and I find that I don't really understand how to do agregate functions. They appear to only be available on IGrouping<K, T>s and it seems I've just got confused.
I need to also ensure that the summaries are calculated server side, pulling back millions of cases would be bad.
Can anybody help me with this one? Is this even possible?
Regards,
James.
-------### UPDATE 1 ###-------
OK, been working on this again today.
I decided to use Linq2SQL to pull pack 2D data and then reformat it using Linq2Objects.
Here is what I started with:
var sql = from clientnames in db.ClientNames
join clientdebttypes in db.ClientDebtTypes on clientnames.ClientID equals clientdebttypes.ClientID
join debttypes in db.DebtTypes on clientdebttypes.DebtTypeID equals debttypes.DebtTypeID
join cases in db.Cases on new { ClientDebtTypeID = clientdebttypes.ClientDebtTypeID } equals new { ClientDebtTypeID = cases.CaseClientDebtTypeID }
group new { clientnames, debttypes, cases } by new
{
clientnames.ClientID,
clientnames.ClientCode,
clientnames.ClientName1,
debttypes.DebtTypeID,
debttypes.DebtTypeShortDesc,
debttypes.DebtTypeLongDesc,
cases.CurrentStateCode
} into g
orderby
g.Key.ClientID,
g.Key.DebtTypeID,
g.Key.CurrentStateCode
select new
{
Client = new Client{ ClientID = g.Key.ClientID, DisplayName = g.Key.ClientName1 },
DebtType = new DebtType{ DebtTypeID = g.Key.DebtTypeID, DisplayName = g.Key.DebtTypeShortDesc, Description = g.Key.DebtTypeLongDesc },
StateSummary = new LoadCaseStatusOverviewScreenOutput.ClientsLocalType.DebtTypesLocalType.StatesCodesLocalType()
{
StateCode = g.Key.CurrentStateCode,
OpenCasesCount = g.Sum(p => 1 - Convert.ToInt32(p.cases.CaseClosed)),
ClosedCasesCount = g.Sum(p => Convert.ToInt32(p.cases.CaseClosed)),
OnHoldCasesCount = g.Sum(p => Convert.ToInt32(p.cases.CaseOnHold)),
ReferredCasesCount = g.Sum(p => Convert.ToInt32(p.cases.CaseReferred)),
TotalCasesCount = g.Count(p => p.cases.CaseID != null),
TotalAmountPaid = g.Sum(p => p.cases.CaseTotalPaid),
TotalAmountOutstanding = g.Sum(p => p.cases.CaseCurrentOutstandingAmount),
TotalAmountWrittenOff = g.Sum(p => p.cases.CaseTotalDebtWrittenOff),
TotalAmountCancelled = g.Sum(p => p.cases.CaseTotalDebtCancelled),
}
};
var res = sql.ToList();
output.Clients = (from results in res
group results by results.Client into resultsByClient
from resultsByDebtType in
(from results in resultsByClient
group results by results.DebtType)
group resultsByDebtType by resultsByClient.Key into resultsByDebtTypeByClient
select new LoadCaseStatusOverviewScreenOutput.ClientsLocalType()
{
Client = resultsByDebtTypeByClient.Key,
DebtTypes = (from resultsByDebtType in resultsByDebtTypeByClient
select new LoadCaseStatusOverviewScreenOutput.ClientsLocalType.DebtTypesLocalType()
{
DebtType = resultsByDebtType.Key,
StatesCodes = (from results in resultsByDebtType
let summary = results.StateSummary
select results.StateSummary).ToList()
}).ToList()
}).ToList();
That runs, but produces one Client/DebtType/Summary set for every result. So even though there is only one client in this case, I end up with 1300 clients, all identical.
I simplified it to the following:
output.Clients = (from results in res
group results by results.Client into resultsByClient
select new LoadCaseStatusOverviewScreenOutput.ClientsLocalType()
{
Client = resultsByClient.Key,
DebtTypes = null,
}).ToList();
That produces 1300 clients. Next I tried this:
output.Clients = (from results in res
group results by results.Client.ClientID into resultsByClient
select new LoadCaseStatusOverviewScreenOutput.ClientsLocalType()
{
Client = new Client { ClientID = resultsByClient.Key },
DebtTypes = null,
}).ToList();
And THAT produces ONE client (hurray!). Except I loose all the client information (boo!)
Guessing that as it's comparing client by refernce instead of by content I wrote the following:
public partial class Client
{
public static bool operator ==(Client left, Client right)
{
return left.ClientID == right.ClientID;
}
public static bool operator !=(Client left, Client right)
{
return left.ClientID != right.ClientID;
}
public override int GetHashCode()
{
return ClientID;
}
}
That did nothing. It repeatedly calls GetHashCode(), which I fudged to force it to return the same hash code for any matching ClientID, but it still created 1300 Client groups.
Regards,
James.
-------### UPDATE 2 ###-------
OK, I thought I would have a go at making the Linq2Sql output only simple values for grouping by:
g.Key.ClientID,
g.Key.ClientName1,
g.Key.DebtTypeID,
g.Key.DebtTypeShortDesc,
g.Key.DebtTypeLongDesc,
And then changed the test Linq2Objects to:
output.Clients = (from results in res
group results by new { ClientID = results.ClientID, DisplayName = results.ClientName1 } into resultsByClient
select new LoadCaseStatusOverviewScreenOutput.ClientsLocalType()
{
Client = new Client { ClientID = resultsByClient.Key.ClientID, DisplayName = resultsByClient.Key.DisplayName },
DebtTypes = null,
}).ToList();
That works. So anonymous types compare in the way I want them to, by content not reference (apparently)
This does not:
output.Clients = (from results in res
group results by new SiDemClient { ClientID = results.ClientID, DisplayName = results.ClientName1 } into resultsByClient
select new LoadCaseStatusOverviewScreenOutput.ClientsLocalType()
{
Client = resultsByClient.Key,//new Client { ClientID = resultsByClient.Key.ClientID, DisplayName = resultsByClient.Key.DisplayName },
DebtTypes = null,
}).ToList();
That still creates 1300 groups.
So, anonymous types compare in a magical way that I don't understand. How can I make my Client class compare like an anonymous type?
Regards,
James.
-------### SOLUTION FOUND ###-------
-------### MANY THANKS TO Enigmativity ###-------
I needed to override the Equals() method instead of implementing the == operator.
Now the grouping works and I have a wonderful Xml document to reutrn!
public partial class SiDemClient
{
public override bool Equals(object obj)
{
if (obj is SiDemClient)
{
return this.ClientID.Equals(((SiDemClient)obj).ClientID);
}
return false;
}
public override int GetHashCode()
{
return ClientID;
}
}
Many Thanks,
James.
When you override GetHashCode you must also override Equals. The == & != operators are irrelevant.
Try with this:
public partial class Client
{
public override bool Equals(object obj)
{
if (obj is Client)
{
return this.ClientID.Equals(((Client)obj).ClientID);
}
return false;
}
public override int GetHashCode()
{
return this.ClientID.GetHashCode();
}
}
See if that helps.

LINQ Right Outer Join Problem

I am writing a right outer join query in SQL Server 2005 and it's working fine, but I am not able to convert it to LINQ.
Here is my query:
select b.number, COUNT(*) AS [AudioCount] from audios a
right join months b on DATEPART(Month, a.[RecordedDate]) = b.number
group by number
Please help me convert it to LINQ.
Thanks & Regards,
Anil Saklania
EDIT: Corrected query.
Depending on what you are looking for I have inverted it to be a left join but it is a left join from months to audio. This will enable you to return a count of zero when a month has no audio recordings. Used paolo's original testing data to test this out.
var audioMonths = from month in ListOfMonths
join audio in ListOfAudios on
month.number equals audio.RecordedDate.Month into audioLeftJoin
from audio in audioLeftJoin.DefaultIfEmpty()
select new
{
Month = month.number,
AudioId = audio != null ? audio.someProperty : null //Need some property on the audio object to see if it exists
};
var monthAudioCount = from audioMonth in audioMonths
group audioMonth by audioMonth.Month into grouping
select new
{
Month = grouping.Key,
AudioCount = grouping.Count(audioMonth => audioMonth.AudioId != null)
};
First, some notes from book: LINQ Pocket Reference by J. & B. Albahari:
1. Using an extra from translates to a SelectMany.
2. An into clause translates to a GroupJoin when it appears directly after a join clause.
Both of the excellent solutions above, by Mike and by Paolo, utilize a second, extra from clause in the query because that translates to a SelectMany.
With SelectMany, a “sequence of sequences” ( a sequence of audio sequences ) is converted into a single flat collection result set. Then, to count the audios, that single flat output collection is, in a second step, grouped according to month. In both solutions above, that is done, and it works OK, but it also necessitates careful checking for nulls.
EXPLOITING THE NATURAL HIERARCHY.
A cleaner alternative way is the use a GroupJoin instead of SelectMany. GroupJoin yields a hierarchical result set, rather than the flat result set of SelectMany. The hierarchical result set needs no grouping, of course, so we eliminate the second step.
Best of all, by utilizing the hierarchical result set of GroupJoin, we don’t have to check for nulls.
Thus we achieve another clean left outer join by this code, and borrowing Paolo's data:
static void Main(string[] args)
{
var ListOfAudios = new List<Audio>() {
new Audio() { someProperty = "test", RecordedDate = new DateTime(2011, 01, 01) },
new Audio() { someProperty = "test", RecordedDate = new DateTime(2011, 01, 02) },
new Audio() { someProperty = "test", RecordedDate = new DateTime(2011, 02, 01) },
new Audio() { someProperty = "test", RecordedDate = new DateTime(2011, 02, 02) }
};
var ListOfMonths = new List<Month>() {
new Month() {number=1, someMonthProperty="testMonth"},
new Month() {number=2, someMonthProperty="testMonth"},
new Month() {number=3, someMonthProperty="testMonth"}
};
var q = from month in ListOfMonths
join audio in ListOfAudios on month.number equals audio.RecordedDate.Month
into hierarch
select new
{
MonthNum = month.number,
AudioCnt = hierarch.Count()
};
foreach (var m in q)
{
Console.WriteLine("{0} - {1}", m.MonthNum,m.AudioCnt);
}
Console.ReadLine();
}
As per some of the comments to your question there are probably more straightforward ways to do what you want than translating your query to linq. However, just as an exercise, here's a way to write it:
var res = from audio in ListOfAudios
join month in ListOfMonths
on audio.RecordedDate.Month equals month.number into joinAudioMonth
from j in joinAudioMonth.DefaultIfEmpty()
group j by j.number into g
select new
{
number = g.Key,
cnt = g.Count()
};
EDIT:
the code above does not do a RIGHT JOIN as you requested, here's a revised one based on Mike's answer. This one does not rely on a property of the Audio object (that might be null even if the object itself exists). But I'm being nitpicky, Mike's answer is basically the correct one.
var audioMonths =
from month in ListOfMonths
join audio in ListOfAudios on
month.number equals audio.RecordedDate.Month into monthAudioJoin
from joined in monthAudioJoin.DefaultIfEmpty()
select new
{
Month = month.number,
J = joined
};
var res = from audioMonth in audioMonths
group audioMonth by audioMonth.Month into grouping
select new
{
number = grouping.Key,
cnt = grouping.Count(a => a.J != null)
};
and here's how I tested it:
public class Audio
{
public string someProperty {get; set;}
public DateTime RecordedDate {get; set; }
}
public class Month
{
public string someMonthProperty {get; set;}
public int number {get; set; }
}
public static void Main (string[] args)
{
var ListOfAudios = new List<Audio>() {
new Audio(){someProperty="test", RecordedDate=new DateTime(2011,01,01)},
new Audio(){someProperty="test", RecordedDate=new DateTime(2011,01,02)},
new Audio(){someProperty="test", RecordedDate=new DateTime(2011,02,01)},
new Audio(){someProperty="test", RecordedDate=new DateTime(2011,02,02)}
};
var ListOfMonths = new List<Month>() {
new Month() {number=1, someMonthProperty="testMonth"},
new Month() {number=2, someMonthProperty="testMonth"},
new Month() {number=3, someMonthProperty="testMonth"}
// ...
};
var audioMonths =
from month in ListOfMonths
join audio in ListOfAudios on
month.number equals audio.RecordedDate.Month into monthAudioJoin
from joined in monthAudioJoin.DefaultIfEmpty()
select new
{
Month = month.number,
J = joined
};
var res = from audioMonth in audioMonths
group audioMonth by audioMonth.Month into grouping
select new
{
number = grouping.Key,
cnt = grouping.Count(a => a.J != null)
};
foreach(var r in res)
{
Console.WriteLine("{0} - {1}", r.number, r.cnt);
}