如何使转换SQL内连接的查询VS实体框架 [英] How to make conversion SQL Inner joins query vs Entity Framework

问题描述

下面是三个表Service_Orders，Project_Services和公司。还有就是服务订单和CompanyID 3表之间的内连接。
我想下面的查询使用C＃或Vb.net转换成具有的Lamda快递实体框架。

 选择前10名*从[Service_Orders]一，[Project_Services] b，[公司] C 
，其中a.so_no = b.service_order和c.companyId = b.compid 
  

解决方案

lambda语法：

  VAR的查询= db.Service_Orders 
。加入（db.Project_Services，
A => a.so_no等于，
B = GT; b.service_order，
（A，b ）=>新建{A，b}）
。加入（db.Company，
X => xbcompid，
C => c.companyId，
（X， C）=>新建{XA，XB，C}）
。取（10）; 
  

更可读的查询语法：

  VAR的查询=（从上a.so_no db.Project_Services一个在db.Service_Orders 
加入b等于b.service_order 
将C在db.Company在b上。 compid等于c.companyId 
选择新{A，b，C}）取（10）。 
  

Here are three tables Service_Orders, Project_Services and Company. There is inner join between 3 tables by Service Order and CompanyID. I want below query to convert into Entity framework with Lamda Express using C# or Vb.net.

select top 10 * from [Service_Orders] a,[Project_Services] b,[Company] c 
where a.so_no = b.service_order and c.companyId = b.compid

解决方案

Lambda syntax:

var query = db.Service_Orders
              .Join(db.Project_Services,
                    a => a.so_no equals,
                    b => b.service_order,
                    (a,b) => new { a, b })
              .Join(db.Company,
                    x => x.b.compid,
                    c => c.companyId,
                    (x,c) => new { x.a, x.b, c })
              .Take(10);

Much more readable query syntax:

var query = (from a in db.Service_Orders
             join b in db.Project_Services on a.so_no equals b.service_order
             join c in db.Company on b.compid equals c.companyId
             select new { a, b, c }).Take(10);

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