Contoh Sintaks Kueri Berbasis Metode: Pengelompokan
Contoh dalam topik ini menunjukkan cara menggunakan metode GroupBy
untuk mengkueri Model Penjualan AdventureWorks menggunakan sintaks kueri berbasis metode. Model Penjualan AdventureWorks yang digunakan dalam contoh ini dibuat dari tabel Kontak, Alamat, Produk, SalesOrderHeader, dan SalesOrderDetail dalam database sampel AdventureWorks.
Contoh dalam topik ini menggunakan pernyataan using
/Imports
berikut:
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
Contoh 1
Contoh berikut menggunakan metode GroupBy
untuk menampilkan objek Address
yang dikelompokkan berdasarkan kode pos. Hasilnya diproyeksikan ke dalam jenis anonim.
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
Contoh 2
Contoh berikut menggunakan metode GroupBy
untuk menampilkan objek Contact
yang dikelompokkan berdasarkan huruf pertama dari nama belakang kontak. Hasilnya juga diurutkan berdasarkan huruf pertama dari nama belakang dan diproyeksikan menjadi jenis anonim.
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
Contoh 3
Contoh berikut menggunakan metode GroupBy
untuk menampilkan objek SalesOrderHeader
yang dikelompokkan berdasarkan ID pelanggan. Jumlah penjualan untuk setiap pelanggan juga ditampilkan.
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