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ObjectQuery<T>::GroupBy Method

Groups the query results by the specified criteria.

Namespace:  System.Data.Objects
Assembly:  System.Data.Entity (in System.Data.Entity.dll)

ObjectQuery<DbDataRecord^>^ GroupBy(
	String^ keys, 
	String^ projection, 
	... array<ObjectParameter^>^ parameters


Type: System::String
The key columns by which to group the results.
Type: System::String
The list of selected properties that defines the projection.
Type: array<System.Data.Objects::ObjectParameter>
Zero or more parameters that are used in this method.

Return Value

Type: System.Data.Objects::ObjectQuery<DbDataRecord>
A new ObjectQuery<T> instance of type DbDataRecord that is equivalent to the original instance with GROUP BY applied.


The query parameter is nullptr or an empty string.


The projection parameter is nullptr or an empty string.

GroupBy applies the projection specified by the projection parameter. This means that the ObjectQuery<T> returned by the GroupBy method is always of type DbDataRecord. For more information, see Object Queries (Entity Framework).

This example is based on the Adventure Works Sales Model.

This example creates a new ObjectQuery<T> object that contains the results of the existing query grouped by product name.

No code example is currently available or this language may not be supported.

This example returns a set of nested data records that contain the Contact.LastName column, grouped and sorted alphabetically by the first letter of Contact.LastName.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4, 3.5 SP1

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.