林克加入哪里？ [英] Linq join where?

问题描述

• entity1 - ID，OwnerCode
  
  
  
  
  • entity2 - OwnerCode，DepartmentCode
  
  

  另外我有一些DepartmentCode

  Also I have some DepartmentCode

  现在我想得到这样的东西（sql语法）：

  Now i want get something like this(sql syntax):

  Select e1.ID 
  from entity1 e1 
  join entity2 e2 on e1.OwnerCode = e2.OwnerCode and e2.DepartmentCode=7
  

  通过Linq

  我写道：

  var q = from e1 in entityes1 
          join e2 in entityes2 on e1.OwnerCode equals e2.OwnerCode ... 
  

  但是如何在这里插入DepartmentCode = 7

  But how insert DepartmentCode=7 here I don't understand.

  推荐答案

  这不是加入表格的一个因素，它是选择记录的一个因素，所以它应该是一个where子句：

  That's not really a factor in joining the tables, it's a factor in selecting records, so it really should be a where clause:

  var q = from e1 in entityes1
          join e2 in entityes2 on e1.OwnerCode equals e2.OwnerCode
          where e2.DepartmentCode == 7
          select e1.ID;
  
  var id = q.Single(); 
  

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