Ejemplos de sintaxis de consulta basada en métodos: AgruparMethod-Based Query Syntax Examples: Grouping

Los ejemplos de este tema muestran cómo usar el GroupBy método para consultar el modelo AdventureWorks Sales utilizando sintaxis de consulta basada en métodos.The examples in this topic show you how to use the GroupBy method to query the AdventureWorks Sales Model using method-based query syntax. El modelo AdventureWorks Sales que se usa en estos ejemplos se crea a partir de las tablas Contact, Address, Product, SalesOrderHeader y SalesOrderDetail de la base de datos de ejemplo AdventureWorks.The AdventureWorks Sales Model that is used in these examples is built from the Contact, Address, Product, SalesOrderHeader, and SalesOrderDetail tables in the AdventureWorks sample database.

Los ejemplos de este tema usan los siguientes using / Imports instrucciones:The examples in this topic use the following using/Imports statements:

using System;
using System.Data;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.Objects;
using System.Globalization;
using System.Data.EntityClient;
using System.Data.SqlClient;
using System.Data.Common;
Option Explicit On
Option Strict On
Imports System.Data.Objects
Imports System.Globalization

EjemploExample

En el ejemplo siguiente se utiliza el método GroupBy para devolver objetos Address agrupados por código postal.The following example uses the GroupBy method to return Address objects that are grouped by postal code. Los resultados se proyectan en un tipo anónimo.The results are projected into an anonymous type.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    var query = context.Addresses
        .GroupBy( address => address.PostalCode);                     
        
    foreach (IGrouping<string, Address> addressGroup in query)
    {
        Console.WriteLine("Postal Code: {0}", addressGroup.Key);
        foreach (Address address in addressGroup)
        {
            Console.WriteLine("\t" + address.AddressLine1 +
                address.AddressLine2);
        }
    }
}
Using context As New AdventureWorksEntities
    Dim query = context.Addresses _
        .GroupBy(Function(Address) Address.PostalCode) _
        .Select(Function(Address) Address)

    For Each addressGroup As IGrouping(Of String, Address) In query
        Console.WriteLine("Postal Code: {0}", addressGroup.Key)
        For Each address As Address In addressGroup

            Console.WriteLine("   " + address.AddressLine1 + address.AddressLine2)
        Next
    Next
End Using

EjemploExample

En el ejemplo siguiente se utiliza el método GroupBy para devolver objetos Contact agrupados por la primera letra del apellido del contacto.The following example uses the GroupBy method to return Contact objects that are grouped by the first letter of the contact's last name. Los resultados se ordenan también por la primera letra del apellido y se proyectan en un tipo anónimo.The results are also sorted by the first letter of the last name and projected into an anonymous type.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    var query = context.Contacts
        .GroupBy(c => c.LastName.Substring(0,1))
        .OrderBy(c => c.Key);

    foreach (IGrouping<string, Contact> group in query)
    {
        Console.WriteLine("Last names that start with the letter '{0}':",
            group.Key);
        foreach (Contact contact in group)
        {
            Console.WriteLine(contact.LastName);
        }
        
    }
}
Using context As New AdventureWorksEntities

    Dim query = context.Contacts _
    .GroupBy(Function(c) c.LastName.Substring(0, 1)) _
    .OrderBy(Function(c) c.Key) _
    .Select(Function(c) c)

    For Each group As IGrouping(Of String, Contact) In query
        Console.WriteLine("Last names that start with the letter '{0}':", group.Key)

        For Each contact As Contact In group

            Console.WriteLine(contact.LastName)
        Next
    Next

End Using

EjemploExample

En el ejemplo siguiente se utiliza el método GroupBy para devolver objetos SalesOrderHeader agrupados por identificador de cliente.The following example uses the GroupBy method to return SalesOrderHeader objects that are grouped by customer ID. También se devuelve el número de ventas para cada cliente.The number of sales for each customer is also returned.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    var query = context.SalesOrderHeaders
        .GroupBy(order => order.CustomerID);
        
    foreach (IGrouping<int, SalesOrderHeader> group in query)
    {
        Console.WriteLine("Customer ID: {0}", group.Key);
        Console.WriteLine("Order count: {0}", group.Count());

        foreach (SalesOrderHeader sale in group)
        {
            Console.WriteLine("   Sale ID: {0}", sale.SalesOrderID);
        }
        Console.WriteLine("");                    
    }
}
Using context As New AdventureWorksEntities

    Dim query = context.SalesOrderHeaders _
        .GroupBy(Function(order) order.CustomerID)

    ' Iterate over each IGrouping
    For Each group In query

        Console.WriteLine("Customer ID: {0}", group.Key)
        Console.WriteLine("Order Count: {0}", group.Count)

        For Each sale In group
            Console.WriteLine("   Sale ID: {0}", sale.SalesOrderID)
        Next

        Console.WriteLine("")

    Next

End Using

Vea tambiénSee also