Aggregate and Grouping functions using LINQ in CRM

By | March 6, 2013
As you know, QueryExpression are built as an Object Model. They support all the features of FetchXML except for grouping & aggregates.

FetchXML supports all the features of QueryExpression including grouping & aggregates. Queries here are built as XML statements.

LINQ queries are built using standard language similar to SQL, but internally it uses QueryExpression and hence it is limited to the features of QueryExppression


The QueryExpressionclass supports complex queries.

The QueryByAttribute class is a simple means to search for entities where attributes matches specified values.



When using LINQ, it returns IQueryable which is not a collection & hence we can’t do group-by or aggregate.



IQueryable queryDemo = from a in orgServiceContext.AccountSet

                                                              where a.Address1_City.Contains(“a”)

                   select a;

 

 
However, LINQ supports group by in following way.


 

Write a simple LINQ Query

var lnqQuery = from o in orgServiceContext.OpportunitySet

where o.EstimatedValue.Value >= 10000

select new

   {

OpportunityTopic = o.Name,

PotentialCustomer = o.CustomerId,

Rating = o.OpportunityRatingCode

};

 

In another query pass your created query as a list. You can either do a ToList() or you can make your own List like List estList = new List() where Groups is your custom class with set & get.

Here, we are using ToList() & grouping the collection by Rating.


 

var lnqQuery2 = (from f in lnqQuery.ToList()


 

//Pass the lnqQuery as a list using ToList() & then group by


 

group f by f.Rating into queryGrp


 

let first = queryGrp.First()


 

//selecting only the first record of all grouped record
 

select new

{

Name = first.OpportunityTopic,

 

Rating = first.Rating.Value

});


 

Now if we want to retrieve all the records from the Query Group, then we can simply create a list of query Group using ToList() & iterate through it as shown in below example

var lnqQuery2 = (from f in lnqQuery.ToList()


 

//Pass the lnqQuery as a list using ToList() & then group by


 

group f by f.Rating into queryGrp


 

//Make a list of queryGrp using ToList()

 

select queryGrp.ToList());


 

//Create a DataTable


 

DataTable table = new DataTable();


 

//Add some columns

 

table.Columns.Add(“Topic”);


 

table.Columns.Add(“Cust”);


 

table.Columns.Add(“Rating”);


 

foreach (var e1 in lnqQuery2)


 

{

//iterate through each record grouped with rating

 

foreach (var e2 in e1)

{

//iterate through each individual record that belongs in a rating

 

DataRow dataRow = table.NewRow();


 

dataRow["Topic"] = e2.OpportunityTopic;


 

dataRow["Cust"] = e2.PotentialCustomer.Name;
 

dataRow["Rating"] = e2.Rating;


 

table.Rows.Add(dataRow);

 }

}

//here you have your list in your dataGridView

 

dataGridView1.DataSource = table;

 

Note- Here we are just showing the rating value. You can get the rating by using FormattedValues["opportunityratingcode"]

For more details you can visit here


Hope this article helps!

                                                                                     

 

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