クエリ式の構文例: フィルター処理 (LINQ to Entities)

[アーティクル]
02/24/2011

このトピックでは、クエリ式の構文で、Where メソッドおよび Where…Contains メソッドを使用して、AdventureWorks Sales Model を照会する例を取り上げます。 Where…Contains はコンパイル済みクエリの中では使用できないことに注意してください。

これらの例で使用されている、AdventureWorks Sales Model は、AdventureWorks サンプルデータベースの Contact、Address、Product、SalesOrderHeader、SalesOrderDetail の各テーブルから作成されています。

このトピックの例には、次の using/Imports ステートメントが使用されています。

Option Explicit On
Option Strict On
Imports System.Data.Objects
Imports System.Globalization

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;

Where

例

次の例では、すべてのオンライン注文が返されます。

Using context As New AdventureWorksEntities
    Dim orders As ObjectSet(Of SalesOrderHeader) = context.SalesOrderHeaders

    Dim onlineOrders = _
        From order In orders _
        Where order.OnlineOrderFlag = True _
        Select New With { _
           .SalesOrderID = order.SalesOrderID, _
           .OrderDate = order.OrderDate, _
           .SalesOrderNumber = order.SalesOrderNumber _
        }

    For Each onlineOrder In onlineOrders
        Console.WriteLine("Order ID: {0} Order date: {1:d} Order number: {2}", _
                onlineOrder.SalesOrderID, _
                onlineOrder.OrderDate, _
                onlineOrder.SalesOrderNumber)
    Next
End Using

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    var onlineOrders =
        from order in context.SalesOrderHeaders
        where order.OnlineOrderFlag == true
        select new
        {
            SalesOrderID = order.SalesOrderID,
            OrderDate = order.OrderDate,
            SalesOrderNumber = order.SalesOrderNumber
        };

    foreach (var onlineOrder in onlineOrders)
    {
        Console.WriteLine("Order ID: {0} Order date: {1:d} Order number: {2}",
            onlineOrder.SalesOrderID,
            onlineOrder.OrderDate,
            onlineOrder.SalesOrderNumber);
    }
}

例

次の例では、注文数量が 3 個以上で 5 個以下の注文が返されます。

Dim orderQtyMin = 2
Dim orderQtyMax = 6
Using context As New AdventureWorksEntities
    Dim orders As ObjectSet(Of SalesOrderDetail) = context.SalesOrderDetails

    Dim query = _
        From order In orders _
        Where order.OrderQty > orderQtyMin And order.OrderQty < orderQtyMax _
        Select New With { _
            .SalesOrderID = order.SalesOrderID, _
            .OrderQty = order.OrderQty _
        }

    For Each order In query
        Console.WriteLine("Order ID: {0} Order quantity: {1}", _
                order.SalesOrderID, order.OrderQty)
    Next
End Using

int orderQtyMin = 2;
int orderQtyMax = 6;
using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    var query =
        from order in context.SalesOrderDetails
        where order.OrderQty > orderQtyMin && order.OrderQty < orderQtyMax
        select new
        {
            SalesOrderID = order.SalesOrderID,
            OrderQty = order.OrderQty
        };

    foreach (var order in query)
    {
        Console.WriteLine("Order ID: {0} Order quantity: {1}",
            order.SalesOrderID, order.OrderQty);
    }
}

例

次の例では、色が赤の製品がすべて返されます。

Dim color = "Red"
Using context As New AdventureWorksEntities
    Dim products As ObjectSet(Of Product) = context.Products

    Dim query = _
        From product In products _
        Where product.Color = color _
        Select New With { _
            .Name = product.Name, _
            .ProductNumber = product.ProductNumber, _
            .ListPrice = product.ListPrice _
        }

    For Each product In query
        Console.WriteLine("Name: {0}", product.Name)
        Console.WriteLine("Product number: {0}", product.ProductNumber)
        Console.WriteLine("List price: ${0}", product.ListPrice)
        Console.WriteLine("")
    Next
End Using

String color = "Red";
using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    var query =
        from product in context.Products
        where product.Color == color
        select new
        {
            Name = product.Name,
            ProductNumber = product.ProductNumber,
            ListPrice = product.ListPrice
        };

    foreach (var product in query)
    {
        Console.WriteLine("Name: {0}", product.Name);
        Console.WriteLine("Product number: {0}", product.ProductNumber);
        Console.WriteLine("List price: ${0}", product.ListPrice);
        Console.WriteLine("");
    }
}

例

次の例では、Where メソッドを使用して、2003 年 12 月 1 日以降に受けた注文を検索します。次に、order.SalesOrderDetail ナビゲーションプロパティを使用して、各注文の詳細を取得します。

Using context As New AdventureWorksEntities
    Dim orders As ObjectSet(Of SalesOrderHeader) = context.SalesOrderHeaders

    Dim query = _
        From order In orders _
        Where order.OrderDate >= New DateTime(2003, 12, 1) _
        Select order

    Console.WriteLine("Orders that were made after December 1, 2003:")
    For Each order In query
        Console.WriteLine("OrderID {0} Order date: {1:d} ", _
                order.SalesOrderID, order.OrderDate)
        For Each orderDetail In order.SalesOrderDetails
            Console.WriteLine("  Product ID: {0} Unit Price {1}", _
                orderDetail.ProductID, orderDetail.UnitPrice)
        Next
    Next
End Using

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    IQueryable<SalesOrderHeader> query =
        from order in context.SalesOrderHeaders
        where order.OrderDate >= new DateTime(2003, 12, 1)
        select order;


    Console.WriteLine("Orders that were made after December 1, 2003:");
    foreach (SalesOrderHeader order in query)
    {
        Console.WriteLine("OrderID {0} Order date: {1:d} ",
            order.SalesOrderID, order.OrderDate);
        foreach (SalesOrderDetail orderDetail in order.SalesOrderDetails)
        {
            Console.WriteLine("  Product ID: {0} Unit Price {1}",
                orderDetail.ProductID, orderDetail.UnitPrice);
        }
    }
}

Where…Contains

例

次の例では、配列を Where…Contains 句の一部として使用し、その配列内の値と一致する ProductModelID を持つすべての製品を検出します。

Using AWEntities As New AdventureWorksEntities()
    Dim productModelIds As System.Nullable(Of Integer)() = {19, 26, 118}
    Dim products = From p In AWEntities.Products _
        Where productModelIds.Contains(p.ProductModelID) _
        Select p
    For Each product In products
        Console.WriteLine("{0}: {1}", product.ProductModelID, product.ProductID)
    Next
End Using

using (AdventureWorksEntities AWEntities = new AdventureWorksEntities())
{
    int?[] productModelIds = {19, 26, 118};
    var products = from p in AWEntities.Products
                   where productModelIds.Contains(p.ProductModelID)
                   select p;
    foreach (var product in products)
    {
        Console.WriteLine("{0}: {1}", product.ProductModelID, product.ProductID);
    }
}

注 :
Where…Contains 句の述語として、Array、List、または IEnumerable インターフェイスを実装する任意の型のコレクションを使用できます。さらに、LINQ to Entities クエリ内でコレクションを宣言および初期化できます。詳細については、次の例を参照してください。

例

次の例では、Where…Contains 句で配列を宣言および初期化し、その配列内の値と一致する ProductModelID または Size を持つすべての製品を検出します。

Using AWEntities As New AdventureWorksEntities()
    Dim products = From p In AWEntities.Products _
        Where (New System.Nullable(Of Integer)() {19, 26, 18}).Contains(p.ProductModelID) _
        OrElse (New String() {"L", "XL"}).Contains(p.Size) _
        Select p
    For Each product In products
        Console.WriteLine("{0}: {1}, {2}", product.ProductID, _
                                           product.ProductModelID, _
                                           product.Size)
    Next
End Using

using (AdventureWorksEntities AWEntities = new AdventureWorksEntities())
{
    var products = from p in AWEntities.Products
                   where (new int?[] { 19, 26, 18 }).Contains(p.ProductModelID) ||
                         (new string[] { "L", "XL" }).Contains(p.Size)
                   select p;
    foreach (var product in products)
    {
        Console.WriteLine("{0}: {1}, {2}", product.ProductID, 
                                           product.ProductModelID, 
                                           product.Size);
    }
}

参照

概念

LINQ to Entities でのクエリ

次の方法で共有

クエリ式の構文例: フィルター処理 (LINQ to Entities)

Where

例

例

例

例

Where…Contains

例

例

参照

概念

その他のリソース