linq group by with count

Question

我试图在linq中编写查询

Select UserId, UserNumber 
FROM User
where UserNumber in
(Select UserNumber
        FROM User
        group by UserNumber
        having Count(UserId) = 1)

Aby暗示？

Answer 1

var query = from u in User
            group u by u.UserNumber into usergroup
            where usergroup.Count() == 1
            from item in usergroup
            select new { item.UserId,item.UserNumber };

Answer 2

如果子查询是你的事，你可以这样做。

var subquery =
  from u in User
  group u by u.UserNumber into g
  where g.Count() = 1
  select g.Key;

var query =
  from u in User
  where subquery.Any(num => num == u.UserNumber)
  select u;