1. 简单形式
var expr = from p in context.Products group p by p.CategoryID into g select g; foreach (var item in expr) { Console.WriteLine(item.Key); foreach (var p in item) { Console.WriteLine("{0}-{1}", p.ProductID, p.ProductName); } }
SELECT [Project2].[CategoryID] AS [CategoryID], [Project2].[C1] AS [C1], [Project2].[ProductID] AS [ProductID], [Project2].[CategoryID1] AS [CategoryID1], [Project2].[ProductName] AS [ProductName], [Project2].[UnitPrice] AS [UnitPrice], [Project2].[UnitsInStock] AS [UnitsInStock], [Project2].[Discontinued] AS [Discontinued] FROM ( SELECT [Distinct1].[CategoryID] AS [CategoryID], [Extent2].[ProductID] AS [ProductID], [Extent2].[CategoryID] AS [CategoryID1], [Extent2].[ProductName] AS [ProductName], [Extent2].[UnitPrice] AS [UnitPrice], [Extent2].[UnitsInStock] AS [UnitsInStock], [Extent2].[Discontinued] AS [Discontinued], CASE WHEN ([Extent2].[ProductID] IS NULL) THEN CAST(NULL AS int) ELSE 1 END AS [C1] FROM (SELECT DISTINCT [Extent1].[CategoryID] AS [CategoryID] FROM [dbo].[Product] AS [Extent1] ) AS [Distinct1] LEFT OUTER JOIN [dbo].[Product] AS [Extent2] ON [Distinct1].[CategoryID] = [Extent2].[CategoryID] ) AS [Project2] ORDER BY [Project2].[CategoryID] ASC, [Project2].[C1] ASC
2. 最大值
var expr = from p in context.Products group p by p.CategoryID into g select new { g.Key, MaxUnitPrice = g.Max(p => p.UnitPrice) }; foreach (var item in expr) { Console.WriteLine("{0}-{1}", item.Key, item.MaxUnitPrice); }
SELECT [GroupBy1].[K1] AS [CategoryID], [GroupBy1].[A1] AS [C1] FROM ( SELECT [Extent1].[CategoryID] AS [K1], MAX([Extent1].[UnitPrice]) AS [A1] FROM [dbo].[Product] AS [Extent1] GROUP BY [Extent1].[CategoryID] ) AS [GroupBy1]
3. 最小值
var expr = from p in context.Products group p by p.CategoryID into g select new { g.Key, MinUnitPrice = g.Min(p => p.UnitPrice) };
SELECT [GroupBy1].[K1] AS [CategoryID], [GroupBy1].[A1] AS [C1] FROM ( SELECT [Extent1].[CategoryID] AS [K1], MIN([Extent1].[UnitPrice]) AS [A1] FROM [dbo].[Product] AS [Extent1] GROUP BY [Extent1].[CategoryID] ) AS [GroupBy1]
4. 平均值
var expr = from p in context.Products group p by p.CategoryID into g select new { g.Key, AverageUnitPrice = g.Average(p => p.UnitPrice) };
SELECT [GroupBy1].[K1] AS [CategoryID], [GroupBy1].[A1] AS [C1] FROM ( SELECT [Extent1].[CategoryID] AS [K1], AVG([Extent1].[UnitPrice]) AS [A1] FROM [dbo].[Product] AS [Extent1] GROUP BY [Extent1].[CategoryID] ) AS [GroupBy1]
5. 求和
var expr = from p in context.Products group p by p.CategoryID into g select new { g.Key, TotalUnitPrice = g.Sum(p => p.UnitPrice) };
SELECT [GroupBy1].[K1] AS [CategoryID], [GroupBy1].[A1] AS [C1] FROM ( SELECT [Extent1].[CategoryID] AS [K1], SUM([Extent1].[UnitPrice]) AS [A1] FROM [dbo].[Product] AS [Extent1] GROUP BY [Extent1].[CategoryID] ) AS [GroupBy1]
6. 计数
var expr = from p in context.Products group p by p.CategoryID into g select new { g.Key, ProductNumber = g.Count() };
SELECT [GroupBy1].[K1] AS [CategoryID], [GroupBy1].[A1] AS [C1] FROM ( SELECT [Extent1].[CategoryID] AS [K1], COUNT(1) AS [A1] FROM [dbo].[Product] AS [Extent1] GROUP BY [Extent1].[CategoryID] ) AS [GroupBy1]
var expr = from p in context.Products group p by p.CategoryID into g select new { g.Key, ProductNumber = g.Count(p => p.UnitsInStock > 0) };
时间: 2024-10-13 19:40:21