求教！这个sql语句怎么用linq实现

[P_Alex]

select top 7 UserName,num from (select u.UserName, SUM(fee)as num  from [dbo].[Users] as u inner join LeaseRecord as l on u.UserID=l.UserID where  l.EndTime>'2017-09-13 15:40:00.000' and l.EndTime<'2017-09-30 15:40:00.000' group by u.UserName) as ResultTab  order by num desc

实现：查找规定时间内的用户名，消费金额，并且统计用户下所用用户消费总金额，最后按照金额进行降序排序，并取出前7条数据
Users 表一
LeaseRecord 表二 （金额：fee）

[hmpzz]

(from u in db.Users
join i in db.LeaseRecord  on a.UserID equals b.UserID 
where
  (String)i.EndTime >= "2017-09-13 15:40:00.000" &&
  (String)i.EndTime <= "2017-09-30 15:40:00.000"
group new {u, i} by new {
  u.UserName
} into g
orderby
  (Decimal?)g.Sum(p => p.i.fee)
select new {
  g.UserName,
  Column1 = (Decimal?)g.Sum(p => p.i.fee)
}).Take(7)