文档介绍：select 描述:查询顾客的公司名、地址信息查询句法: var 构建匿名类型 1= from c in select new {公司名= panyName, 地址= }; 对应 SQL : SELECT [t0].[CompanyName], [t0].[Address] FROM [dbo].[Customers] AS [t0] 描述:查询职员的姓名和雇用年份查询句法: var 构建匿名类型 2= from emp in select new {姓名= + , 雇用年= }; 对应 SQL : SELECT [t0].[LastName] + [t0].[FirstName] AS [value], DATEPART(Year, [t0].[HireDat e]) AS [value2] FROM [dbo].[Employees] AS [t0] 描述:查询顾客的 ID 以及联系信息(职位和联系人) 查询句法: var 构建匿名类型 3= from c in select new { ID = , 联系信息= new {职位= , 联系人= } }; 对应 SQL : SELECT [t0].[CustomerID], [t0].[ContactTitle], [t0].[ContactName] FROM [dbo].[Customers] AS [t0] 描述:查询订单号和订单是否超重的信息查询句法: var select 带条件= from o in select new {订单号= , 是否超重= > 100 ?"是":"否" }; 对应 SQL : SELECT [t0].[OrderID], (CASE WHEN [t0].[Freight] > ***@p0 THEN ***@p1 ELSE ***@p2 END) AS [value] FROM [dbo].[Orders] AS [t0] -- ***@p0: Input Currency (Size = 0; Prec = 19; Scale = 4) [100] -- ***@p1: Input String (Size = 1; Prec = 0; Scale = 0) [是] -- ***@p2: Input String (Size = 1; Prec = 0; Scale = 0) [否] where 描述:查询顾客的国家、城市和订单数信息,要求国家是法国并且订单数大于 5 查询句法: var 多条件= from c in where == "France" && >5 select new {国家= , 城市= , 订单数= }; 对应 SQL : SELECT [t0].[Country], [t0].[City], ( SELECT COUNT(*) FROM [dbo].[Orders] AS [t2] WHERE [t2].[CustomerID] = [t0].[CustomerID] ) AS [value] FROM [dbo].[Customers] AS [t0] WHERE ([t0].[Country] = ***@p0) AND ((( SELECT COUNT(*) FROM [dbo].[Orders] AS [t1] WHERE [t1].[CustomerID] = [t0].[CustomerID] )) > ***@p1) -- ***@p0: Input String (Size = 6; Prec = 0; Scale = 0) [France] -- ***@p1: Input Int32 (Size = 0; Prec = 0; Scale = 0) [5] orderby 描述:查询所有没有下属雇员的雇用年和名,按照雇用年倒序,按照名正序查询句法: var 排序= from emp in where == 0 orderby descending , ascending select new {雇用年=