Question

即时通讯使用vs2010并有一个sql语句如下所示

select deptId, deptName, Detail from lkDept where deptId in (select deptId from lkDeptLinks where userRef in (select ref from lkUsers where userId = @userId)) order by deptName

我需要将上面转换为linq语句，lambda会很好

所有表都在dbml

中

这是我到目前为止的混乱，显然它不会起作用

var queryUsers = dc.lkUsers.Where(p => p.UserID == userId);
var queryLinks = dc.lkDeptLinks.Where(p => queryUsers.ref.contains(p.ref));
var queryDept = dc.lkDepts.Where(p => queryLinks.deptid.contains(p.deptid));

任何帮助都会得到应用并提前致谢

好的，谢谢你们的帮助，我最终得到了像这样的东西

  using (var dc = new myDataContext(DB.GetConnectionString()))
  {
      var queryUsers = dc.lkUsers.Where(p => p.UserID == userId).Select(p => p.@ref); 
      var queryLinks = dc.lkDeptLinks.Where(p => queryUsers.Any(x => p.UserRef  == x )).Select(p => p.DeptId);
      var queryDept = dc.lkDepts.Where(p => queryLinks.Any(x => p.DeptID == x)).OrderBy(p => p.deptName).Select(p => new SLDepartment(p));

      if (queryDept.Any())
        return new SLDepartments(queryDept);

  }

请注意构造函数，SlDepartment（lkDept dept）和SlDepartments（IEnumerable集合）是否适合使用LINQ？

任何遗漏我可能会失踪，即上述或整个解决方案的异常或性能问题的可能性？

Answer 1

您的尝试似乎是正确的但只是应该更改包含 - ＆gt;任何也是不完整的：

var queryUsers = dc.lkUsers.Where(p => p.UserID == userId);
var queryLinks = dc.lkDeptLinks.Where(p => queryUsers.ref.Any(x=>x== p));
var queryDept = dc.lkDepts.Where(p => queryLinks.deptid.Any(x=> x == p.deptid));
return  queryDept
        .Select(x=>new {ID = x.deptId, Name = x.deptName, Detail = x.Detail})
        .ToList();

将嵌套的“select in”语句转换为LINQ lambda

1 个答案: