LINQ系列：LINQ to SQL Exists/In/Any/All/Contains

1. Any

　　返回没有Product的Category

var expr = from c in context.Categorieswhere !c.Products.Any()select c;

SELECT [Extent1].[CategoryID] AS [CategoryID], [Extent1].[CategoryName] AS [CategoryName]FROM [dbo].[Category] AS [Extent1]WHERE  NOT EXISTS (SELECT 1 AS [C1]FROM [dbo].[Product] AS [Extent2]WHERE [Extent1].[CategoryID] = [Extent2].[CategoryID])

var expr = from c in context.Categorieswhere !c.Products.Any(p => p.UnitPrice > 10m)select c;

SELECT [Extent1].[CategoryID] AS [CategoryID], [Extent1].[CategoryName] AS [CategoryName]FROM [dbo].[Category] AS [Extent1]WHERE  NOT EXISTS (SELECT 1 AS [C1]FROM [dbo].[Product] AS [Extent2]WHERE ([Extent1].[CategoryID] = [Extent2].[CategoryID]) AND ([Extent2].[UnitPrice] > cast(10 as decimal(18))))

2. All

var expr = from c in context.Categorieswhere c.Products.All(p => p.Discontinued)select c;

SELECT [Extent1].[CategoryID] AS [CategoryID], [Extent1].[CategoryName] AS [CategoryName]FROM [dbo].[Category] AS [Extent1]WHERE  NOT EXISTS (SELECT 1 AS [C1]FROM [dbo].[Product] AS [Extent2]WHERE ([Extent1].[CategoryID] = [Extent2].[CategoryID]) AND ([Extent2].[Discontinued] <> cast(1 as bit)))

3. Contains

var expr = from p in context.Productswhere new string[] { "LINQ to Object","LINQ to ADO.NET", "LINQ to XML" }.Contains(p.ProductName)select p;

SELECT [Extent1].[ProductID] AS [ProductID], [Extent1].[CategoryID] AS [CategoryID], [Extent1].[ProductName] AS [ProductName], [Extent1].[UnitPrice] AS [UnitPrice], [Extent1].[UnitsInStock] AS [UnitsInStock], [Extent1].[Discontinued] AS [Discontinued]FROM [dbo].[Product] AS [Extent1]WHERE [Extent1].[ProductName] IN (N'LINQ to Object', N'LINQ to ADO.NET', N'LINQ to XML')

var expr = from p in context.Productswhere !(new string[] { "LINQ to Object","LINQ to ADO.NET", "LINQ to XML" }).Contains(p.ProductName)select p;

SELECT [Extent1].[ProductID] AS [ProductID], [Extent1].[CategoryID] AS [CategoryID], [Extent1].[ProductName] AS [ProductName], [Extent1].[UnitPrice] AS [UnitPrice], [Extent1].[UnitsInStock] AS [UnitsInStock], [Extent1].[Discontinued] AS [Discontinued]FROM [dbo].[Product] AS [Extent1]WHERE  NOT ([Extent1].[ProductName] IN (N'LINQ to Object', N'LINQ to ADO.NET', N'LINQ to XML'))

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