Linq中的相关子查询

Question

我有一张员工桌子和EmployeeCourseStatus桌子.

我想显示每个员工的列表,其中包含已完成的课程数(status = "CMP").

我有以下相关子查询,导致以下错误:

var query = (from emp in Employee
                     join adr in EmployeeAddress on emp.id = adr.EmployeeID
                     select new
                     {
                        id = emp.id,
                        name=emp.name,
                        country=adr.country,
                        CompletedCourseCount = (from c in employeeCourseStatus where c.empid = emp.id && c.status == "CMP" select c.id).count()
                     }

错误:

仅支持Premitive类型.

等效的SQL子查询将是 -

Select emp.id
       , emp.name
       , adr.Country
       , CompletedCourseCount = (select count(id) from EmployeeCourseStatus where id = emp.id and status = "CMP") 
from   Employee emp
       JOIN employeeaddress adr ON adr.EmployeeID = emp.ID

Answer 1

请尝试在计数查询中where c.empid = emp.id替换为。where c.empid == emp.id

如果这不起作用，那么emp.name和的类型是什么adr.country？