将 SQL 转换为 LINQ 到实体 WHERE IN 子句

Question

如何将此 sql 语句转换为 LINQ to Entities？

SQL 语句：

Select * from Departments where DepartmentID  in (Select DepartmentID from Employees where FirstName like '%FirstName%' or LastName like '%LastName%')

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我只有 WHERE =(equals) ，我不能做 WHERE IN 子句

LINQ to 实体：

from t in db.Departments
where
  t.DepartmentID == -->Should be IN not EQUALS
    ((from t0 in db.Employees
    where
      t0.FirstName.Contains("FirstName") ||
      t0.LastName.Contains("LastName")
    select new {
      t0.DepartmentID
    }).FirstOrDefault().DepartmentID)
select t

Answer 1

(from d in db.Departments
 join e in db.Employees
     on d.DepartmentID equals e.DepartmentID
 where e.FirstName.Contains("FirstName") ||
       e.LastName.Contains("LastName")
 select t).Distinct()

Answer 2

你可以用这个

var x = 
    (from t0 in db.Employees
    where
      t0.FirstName.Contains("FirstName") ||
      t0.LastName.Contains("LastName")
    select new {
      t0.DepartmentID
    }).FirstOrDefault().DepartmentID;

from t in db.Departments
where
  t.DepartmentID.contains(x.DepartmentID)
select t