SELECT (SELECT d.DeptName FROM Dept d WHERE d.Id=p.DeptId) DeptName, count( p.DeptId) AS Count FROM Person pGROUP BY p.DeptIdvar dept = (from p in db.Person group p by p.DeptId into g join d in db.Dept on g.Key equals d.Id select new {count = g.Count (), g.Key, DeptName = d.DeptName}) .ToList (); Search Microsoft Knowledge Add msdn en-us=>zh-cn