What's the equivalent LINQ instruction for a Datatable of the following SQL query:
SELECT code_direction, count(TP) AS CN
FROM table1
WHERE cod_time = 'A011'
GROUP BY TP,code_direction;
and how to get the result into a new datatable?
I tried to convert it but I there're some errors. Someone could take a look on this:
var query = from t in table1.AsEnumerable()
group t by new { t.TP, t.code_direction }
into grp
select new
{
grp.Key.code_direction,
CN = grp.Count(t.TP)
};
foreach (var x in query)
{
Console.Write(x.code_direction);
Console.Write(x.CN);
}
As far as your first question goes. The LINQ equivalent of the SQL query is:
var query = from t in table1.AsEnumerable()
where t.cod_time == "A011"
group t by new { t.TP, t.code_direction }
into grp
select new
{
grp.Key.code_direction,
CN = grp.Count()
};
Note that you don't have to pass any argument to grp.Count(). (For the obvious reason that in SQL COUNT(TP) is the same as COUNT(*), i.e. just count the number of rows. The story would be different if you'd use COUNT(DISTINCT TP) or similar.)
As far as the second question goes, if your query just returned an IEnumerable<T> where T is DataRow (i.e. a query like table1.AsEnumerable().Where(r => r.cod_time == "A011")) then you could just the DataTableExtensions.CopyToDataTable extension method. As your query returns an anonymous type however, you will have to follow these instructions found on MSDN.
I Have been using LINQ to work on a JSON object returned from a remote sharepoint web service. I have posted this because most of the answers I found online were slightly different from what I needed.
a json list of daily activities is returned from a remote sharepoint list & is then summarised using LINQ
The simplified version of a custom object definition is shown below( & which is defined in the models area of an MVC application)
public class MyCustomObjectList
{
public string eventdate { get; set; }
public string userid { get; set; }
public string action { get; set; }
}
The JSON object is serialised into a MyCustomObjectList array.
var customobject = serializer.Deserialize<MyCustomObjectList>(jsonobject);
I wanted to work out how many actions of each type happened on a given day. NB eventdate is stored as a string in format yyyy-mm-dd hh:MM:ss. This was to simplify conversions between c#, JSON & Jquery ( where required I create DateTime objects elsewhere in the code using the
eventdate.
Some will argue this is inefficient, but I prefer to split processes into a sequential set of really simple operations, for the sake of easier debugging & to help other people follow my code. Thats why there are 2 Linq queries .
querya strips out the time component from the eventdate This ensures our later grouping happens by day, & not by second. To be doubly sure that there is no caching, I create it in a new field called actionday. I also rename action to activity, because intellisense was getting confused!! The other columns are copied as is.
var querya =
from c in customobject.rows
select new { actionday = c.eventdate.Substring(0, 10), activity = c.action, c.userid,
c.eventdate };
/* queryb produces a grouped count of querya, grouped on actionday & activity, creating new columns actionkey,ActionCount,Dte,action & DetailList ( which is a summary for debugging purposes)
*/
var queryb=
from p in querya group p by new { p.actionday, p.activity} into idGroup
actionkey = idGroup.Key,
ActionCount = idGroup.Count(),
Dte = idGroup.Key.actionday,
action = idGroup.Key.activity,
DetailList = idGroup
};
Here’s a version that sumarises by 3 columns
var queryc = from p in querya
group p by new { p.actionday, p.userid, p.activity} into idGroup
select new
{
actionday = idGroup.Key,
ActionCount = idGroup.Count(),
userid = idGroup.Key.userid,
Dte = idGroup.Key.actionday,
action = idGroup.Key.activity,
DetailList = idGroup
};
Related
I have an existing LINQ query that I am trying to optimize. I have the following entity Types (simplified)
public class Account
{
public int Id { get; set; }
public IEnumerable<OpportunityInfo> Opportunities { get; set; }
}
public class Opportunity
{
public int Id { get; set; }
public string Name { get; set; }
public bool Active { get; set; }
public IEnumerable<Quote> Quotes { get; set; }
}
public class Quote
{
}
It is a standard hierarchy of Account to Opportunity to Quote. Nothing Special. I have the following query that I am using on an ASP.NET Core controller index method. I am starting from Quote and working backwards because there is dynamic query logic between the query and opportunityQuotes that must be Quote based. Otherwise I would start from the top direction.
var query = from o in Quotes select o;
additional query logic (filtering and sorting)
var opportunityQuotes = from o in query
group o by new
{
accountId = o.Opportunity.AccountId,
accountName = o.Opportunity.Account.Name,
active = o.Opportunity.Account.Active,
}
into p
select new
{
Id = p.Key.accountId,
Name = p.Key.accountName,
Active = p.Key.active,
Opportunities =
(from q in p
group q by new
{
Id = q.Opportunity.Id,
Name = q.Opportunity.Name,
Active = q.Opportunity.Active
}
into r
select new
{
Name = r.Key.Name,
Id = r.Key.Id,
Active = r.Key.Active,
Quotes = r
})
};
opportunityQuotes.Dump();
This query generates the following SQL.
SELECT [o].[Id], [o].[ARRValue], [o].[AccountId], [o].[AdjustedArr], ...
FROM [Quotes] AS [o]
LEFT JOIN [Opportunities] AS [o.Opportunity] ON [o].[OpportunityId] = [o.Opportunity].[Id]
INNER JOIN [Accounts] AS [o.Account] ON [o].[AccountId] = [o.Account].[Id]
ORDER BY [o].[AccountId], [o.Account].[Name], [o.Account].[Active]
GO
SELECT [q.Opportunity0].[Id], [q.Opportunity0].[Name], [q.Opportunity0].[Active]
FROM [Opportunities] AS [q.Opportunity0]
GO
SELECT [q.Opportunity0].[Id], [q.Opportunity0].[Name], [q.Opportunity0].[Active]
FROM [Opportunities] AS [q.Opportunity0]
GO
SELECT [q.Opportunity0].[Id], [q.Opportunity0].[Name], [q.Opportunity0].[Active]
FROM [Opportunities] AS [q.Opportunity0]
GO
In reality it generates on query for each opportunity, but I left that out for brevity sake. In my opinion EF should not generate a separate query for each quote. In fact if I comment out the .Name and .Active key parameters in the query as shown below:
group q by new
{
Id = q.Opportunity.Id,
// Name = q.Opportunity.Name,
// Active = q.Opportunity.Active
}
and comment out the correspond variables in the select clause it generates much cleaner sql.
SELECT [o].[Id], [o].[ARRValue], [o].[AccountId], ...
FROM [Quotes] AS [o]
LEFT JOIN [Opportunities] AS [o.Opportunity] ON [o].[OpportunityId] = [o.Opportunity].[Id]
INNER JOIN [Accounts] AS [o.Account] ON [o].[AccountId] = [o.Account].[Id]
ORDER BY [o].[AccountId], [o.Account].[Name], [o.Account].[Active]
GO
The reason I am confused is that .Name and .Active are in the exact same object, they are grouped in the key in the same way as the .Id field, and therefore I don't see why EF would change its behavior just by adding additional group values. Can someone explain the behavior?
Let's take a step back and look at it from a different perspective: If you were to write the SQL query manually, and wanted to fetch all the data required in one query, you would get a lot of duplicate data for the opportunities and account. You could also do this here:
var query = from o in Quotes select o;
var oppQuotes = from o in query
select new
{
AccountId = o.Opportunity.Account.Id,
AccountName = o.Opportunity.Account.Name,
// ... and so on, with all the fields you expect to use.
OpportunityId = o.Opportunity.Id,
OpportunityName = o.Opportunity.Name,
// ... and so on, with all the fields you expect to use.
QuoteId = o.Id,
QuoteName = o.Name,
// ... and again, you get the point.
};
Then, just do an .AsEnumerable() on it, and perform the grouping in your C# code. The database won't be able to optimize anything anyways.
var opportunityQuotes = from q in oppQuotes.AsEnumerable()
group q by new { q.AccountId, q.AccountName }
into accounts
// ... and so on.
For your question, why EF is creating the strange query, I'm at a loss.
In any case, it is always good to be thinking about how YOU would create the sql code to get the data you want most efficiently and not rely on EF to "do the right thing". In many cases it will, in others it will completely blow up in your face. When you want a query, think of the SQL and then translate that to EF code. If you tell it specifically, what you want, you will get it.
I am experimenting with the example CalculatePrice on the Dynamics CRM example page.
And im having a hard time understanding how to get products and bundles in a good manner.
What i wanna try and do is get products from an order with a productstructure attribute and a producttypecode. But it seems whatever i try i get a error The given key was not present in the dictionary.
The query below should look for productID from salesorder based on productID
QueryExpression query = new QueryExpression("salesorderdetail");
query.ColumnSet.AddColumns("quantity", "salesorderispricelocked", "priceperunit", "producttypecode", "_productid_value");
query.Criteria.AddCondition("salesorderid", ConditionOperator.Equal, entity.Id);
QueryExpression query2 = new QueryExpression("product");
query2.ColumnSet.AddColumns("productstructure", "productnumber" , "productid");
query.Criteria.AddCondition("productid", ConditionOperator.Equal, ec.Entities["_productid_value"]);
Then i try to iterate the list of objects to see if they have productstructure and their producttypecode
for (int i = 0; i < ec.Entities.Count; i++)
{
if (ec.Entities[i].GetAttributeValue<int>("producttypecode") == 6)
{ you are a product
if (ec.Entities[i].GetAttributeValue<int>("productstructure") == 3){ you are a bundle
This is the link to the sample code i use:
https://learn.microsoft.com/en-us/dynamics365/customer-engagement/developer/sample-calculate-price-plugin
For starters, the _productid_value notation is the WebAPI's way to access a lookup field. To access the productid using the SDK's late-bound paradigm, use:
myEntity["productid"] or
myEntity.GetAttributeValue<Guid>("productid") or
myEntity.GetAttributeValue<EntityReference>("productid").
Beyond that, since Product is a lookup on the OrderDetail, using a couple LinkEntity objects you could get away with a single query.
I would probably use LINQ and do something like this:
private void getProducts(Guid salesOrderId)
{
using (var context = new Microsoft.Xrm.Sdk.Client.OrganizationServiceContext(svc))
{
var query = from od in context.CreateQuery("salesorderdetail")
join so in context.CreateQuery("salesorder")
on od.GetAttributeValue<Guid>("salesorderid") equals so.GetAttributeValue<Guid>("salesorderid")
join p in context.CreateQuery("product")
on od.GetAttributeValue<Guid>("productid") equals p.GetAttributeValue<Guid>("productid")
where od.GetAttributeValue<Guid>("salesorderid").Equals(salesOrderId)
select new
{
OrderDetailId = od.GetAttributeValue<Guid>("salesorderdetailid"),
ProductId = od.GetAttributeValue<EntityReference>("productid"),
Quantity = od.GetAttributeValue<decimal?>("quantity"),
IsPriceLocked = so.GetAttributeValue<bool?>("ispricelocked"),
PricePerUnit = od.GetAttributeValue<Money>("priceperunit"),
ProductTypeCode = od.GetAttributeValue<OptionSetValue>("producttypecode"),
ProductStructure = p.GetAttributeValue<OptionSetValue>("productstructure"),
ProductNumber = p.GetAttributeValue<string>("productnumber")
};
var results = query.ToList();
var products = results.Where(e => e.ProductStructure.Value == 6).ToList();
var bundles = results.Where(e => e.ProductStructure.Value == 3).ToList();
}
}
Please note that local variables results, products, and bundles are an anonymous type. You can loop through and access the properties of each object, but there's also a strong chance you'd want to cast them into instances of a real class.
Consider the LINQ code :
var objs = (ClientsDB.Context.ClientProcessed.GroupBy(grp => new
{
City = grp.City,
Day = grp.Insert_Date.Value.Day,
Month = grp.Insert_Date.Value.Month,
Year = grp.Insert_Date.Value.Year
})....
var objs = (ClientsDB.Context.ClientProcessed.GroupBy(grp => new
{
Department = grp.Department,
Day = grp.Insert_Date.Value.Day,
Month = grp.Insert_Date.Value.Month,
Year = grp.Insert_Date.Value.Year
})....
var objs = (ClientsDB.Context.ClientProcessed.GroupBy(grp => new
{
State = grp.State,
Day = grp.Insert_Date.Value.Day,
Month = grp.Insert_Date.Value.Month,
Year = grp.Insert_Date.Value.Year
})....
How can I have GroupBy done by a specific column passed as a string ?
For example :
String grpByParam = "City"; // grpByParam = "State"; // String grpByParam = "Department";
And then pass that param to a linq query , instead of duplicating LINQ queries every now and again .
FYI , I need that as LINQ-TO-SQL and not LINQ-TO-OBJECTS query , meaning I want the filtering to be done in the DB , and not in the memory .
Is that possible ?
Thanks
You can check the string value and call GroupBy based on that
if (grpByParam.Equals("City")) {
result = source.GroupBy(a => a.City);
} ...
You can implement a method which takes a source (the LINQ query without the GroupBy) and return a result (the result of GroupBy)
See
This method is implemented by using deferred execution. The immediate
return value is an object that stores all the information that is
required to perform the action. The query represented by this method
is not executed until the object is enumerated either by calling its
GetEnumerator method directly or by using foreach in Visual C# or For
Each in Visual Basic.
in the docs.
I have searching for a while now, but couldn't find how to query from public view. For example, I have predefined public view called Active Accounts and I want data from it.
So far I only know this way, but that not include any views:
using (var xrm = new XrmServiceContext("Xrm"))
{
var activeAccounts = from a in xrm.AccountSet
where a.StateCode == 0
select new { a.Id, a.Name };
// TODO ...
}
But I would like to do it like this (not working, ActiveAccountsView not exist, it's pseudo):
using (var xrm = new XrmServiceContext("Xrm"))
{
var activeAccounts = from a in xrm.ActiveAccountsView
select new { a.Id, a.Name };
// TODO ...
}
Is this even possible?
The query definitions of public views are stored in the savedquery entity, that can be queried using common techniques.
Out-of-the-box views are stored with a fixed ID, so querying Active Accounts on the OrganizationServiceContext object could be done in the following way:
private static IEnumerable<Entity> GetActiveAccounts(OrganizationServiceContext serviceContext)
{
string fetchXml = serviceContext
.CreateQuery("savedquery")
.Where(sq =>
sq.GetAttributeValue<Guid>("savedqueryid") == new Guid("00000000-0000-0000-00AA-000010001002"))
.Select(sq => sq.GetAttributeValue<string>("fetchxml"))
.First();
var request = new RetrieveMultipleRequest
{
Query = new FetchExpression(fetchXml)
};
var response = (RetrieveMultipleResponse) serviceContext.Execute(request);
return response.EntityCollection.Entities;
}
It is not possible to use LINQ here. LINQ relies on the QueryExpression class, but does not implement all its capabilities (OUTER JOIN is a painful omission for example). So, while it is possible to convert a LINQ query to a QueryExpression, the other way around is not.
Paging can be applied by editing the Fetch XML string, but if that is too much hassle, you can also consider to convert the Fetch XML to a QueryExpression and apply paging on that object:
private IEnumerable<Entity> GetActiveAccounts(int pageNumber)
{
string fetchXml = _serviceContext
.CreateQuery("savedquery")
.Where(sq =>
sq.GetAttributeValue<Guid>("savedqueryid") == new Guid("00000000-0000-0000-00AA-000010001002"))
.Select(sq => sq.GetAttributeValue<string>("fetchxml"))
.First();
var conversionRequest = new FetchXmlToQueryExpressionRequest
{
FetchXml = fetchXml
};
var response = (FetchXmlToQueryExpressionResponse)_serviceContext.Execute(conversionRequest);
response.Query.PageInfo = new PagingInfo { Count = 1, PageNumber = pageNumber };
var queryRequest = new RetrieveMultipleRequest
{
Query = response.Query
};
var result = (RetrieveMultipleResponse) _serviceContext.Execute(queryRequest);
return result.EntityCollection.Entities;
}
Additional advantage of the QueryExpression vs. Fetch XML is that it is processed in a bit more efficient way.
The very same can be done with user defined views; these views are stored in the userquery entity. The only difference here is you cannot rely on a fixed view ID. Instead you would need to filter your query on querytype, name, returnedtypecode, ownerid and/or other criteria.
Dynamics CRM also has an OrganizationRequest that allows you to execute the savedquery immediately. However, it returns its result as a resultset XML string, so you would still need to deserialize the response. (A nice example can be found here.) Also, I am not sure if it is possible to limit the result set to a specific page when using the ExecuteByIdSavedQueryRequest:
var request = new ExecuteByIdSavedQueryRequest
{
EntityId = new Guid("00000000-0000-0000-00AA-000010001002")
};
var response = (ExecuteByIdSavedQueryResponse)serviceContext.Execute(request);
string resultset = response.String;
I have Two classes Named OfflineOrderLineItem.cs and OnlineOrderLineItem.cs both have diff Order table named offline and Online
In that i want to Combine the two tables data to search and Display the Fields from both tables
How to do that using linq in mvc4 ??? any idea.....
public virtual IPagedList<OnlineOrderLineItem> SearchOrderLineItems(string PoNumber)
{
var query1 = (from ol in _offlineOrderLineItemRepository.Table
select new
{
ol.Name
}).ToList();
var query2 = (from opv in _onlineOrderLineItemRepository.Table
select new
{
opv.Name
}).ToList();
var finalquery = query1.Union(query2);
if (!String.IsNullOrWhiteSpace(Name))
finalquery = finalquery.Where(c => c.Name == Name);
var orderlineitems = finalquery.ToList(); //its not working it throw a error
return new PagedList<OnlineOrderLineItem>(orderlineitems);//error
}
Error
cannot convert from 'System.Collections.Generic.List<AnonymousType#1>'
to 'System.Linq.IQueryable<Nop.Core.Domain.Management.OnlineOrderLineItem>'
to 'System.Linq.IQueryable<Nop.Core.Domain.Management.OnlineOrderLineItem>'
query1 and query2 are lists of an anonymous type with a single property of type string. (I assmume the ol.Name and opv.Name are strings.) Hence finalQuery and orderlineitems are collections of this anonymous as well. By specifying PagedList<T> you require that the collection passed into the constructor is an enumeration of type T. T is OnlineOrderLineItem, but the enumeration passed into the constructor is the anonymous type which is a different type. Result: compiler error.
To solve the problem I suggest that you define a named helper type that you can use to union the two different types OfflineOrderLineItem and OnlineOrderLineItem:
public class OrderLineItemViewModel
{
public int Id { get; set; }
public string PoNumber { get; set; }
public string Name { get; set; }
// maybe more common properties of `OfflineOrderLineItem`
// and `OnlineOrderLineItem`
}
Then your SearchOrderLineItems method should return a paged list of that helper type:
public virtual IPagedList<OrderLineItemViewModel> SearchOrderLineItems(
string PoNumber)
{
var query1 = from ol in _offlineOrderLineItemRepository.Table
select new OrderLineItemViewModel
{
Id = ol.Id,
PoNumber = ol.PoNumber,
Name = ol.Name,
// maybe more properties
};
// don't use ToList here, so that the later Union and filter
// can be executed in the database
var query2 = from opv in _onlineOrderLineItemRepository.Table
select new OrderLineItemViewModel
{
Id = opv.Id,
PoNumber = opv.PoNumber,
Name = opv.Name,
// maybe more properties
};
// don't use ToList here, so that the later Union and filter
// can be executed in the database
var finalquery = query1.Union(query2);
// again no ToList here
if (!string.IsNullOrWhiteSpace(PoNumber))
finalquery = finalquery.Where(c => c.PoNumber == PoNumber);
var orderlineitems = finalquery.ToList(); // DB query runs here
return new PagedList<OrderLineItemViewModel>(orderlineitems);
}
It is important to use ToList only at the very end of the query. Otherwise you would load the whole tables of all OnlineOrderLineItems and all OfflineOrderLineItems into memory and then filter out the items with the given PoNumber in memory which would be a big overhead and performance desaster.
Instead of
var orderlineitems = finalquery.ToList();
Try
var orderlineitems = finalquery.AsQueryable();
From https://github.com/TroyGoode/PagedList/blob/master/src/PagedList/PagedList.cs, PagedList takes a IQueryable<T>
Queryable.AsQueryable<TElement> Method