IFulltextQueryTDocumentGroupByTKey(ExpressionFuncTDocument, TKey) Method

Group the results of this query by the given key.

Definition

Namespace: SphinxConnector.FluentApi
Assembly: SphinxConnector (in SphinxConnector.dll) Version: 6.1.0

C#

IFulltextQuery<TDocument> GroupBy<TKey>(
	Expression<Func<TDocument, TKey>> keySelector
)

VB

Function GroupBy(Of TKey) ( 
	keySelector As Expression(Of Func(Of TDocument, TKey))
) As IFulltextQuery(Of TDocument)

Parameters

keySelector ExpressionFuncTDocument, TKey: A function to extract the key from a document.

Type Parameters

TKey: The type of the key returned by the function that is represented by keySelector.

Return Value

IFulltextQueryTDocument
The current instance.

Example

To group by multiple attributes, create an anonymous type with the attributes to group by:

C#

using (IFulltextSession fulltextSession = fulltextStore.StartSession())
{
    var results = fulltextSession.Query<Product>().
                                  Match("a product").
                                  GroupBy(p => new { p.CategoryId, p.VendorId }).
                                  Select(p => new
                                  {
                                      p,
                                      Count = Projection.Count()        
                                  }).ToList();
 }

Note that grouping by multiple attributes is only supported with Sphinx 2.1.2 and above.

Exceptions

ArgumentNullException	Occurs when keySelector is null.
InvalidOperationException	Occurs when this method called more than once for query.