我在NHibernate中需要这个查询，使用paging：

SELECT TOP(page_size)
FROM AppUser this_ left join
 (select UserPrinciples.*
 from  (select UserPrinciples.*,
         row_number() over (partition by UserName order by User_Id) as seqnum
        from UserPrinciples
        ) UserPrinciples
 where seqnum = 1) as b 

 on this_.User_Id=b.User_ID

我现在的相关代码是：

（ AppUser由IUser重新播放; UserPrinciples由StoredCredentials重播）

public UserPagedQuery(ISessionProvider<ISession> sessionProvider)
{
    _sessionProvider = sessionProvider;
    _query = sessionProvider.Session.QueryOver<IUser>();

    var uc = _query.UnderlyingCriteria;
    var ap = uc.GetOrCreateAssociationPath("StoredCredentials");
    ap.AddOrder(Order.Asc("UserName"));
}

public IEnumerable<IUser> Execute()
{
    var pagedReceiving = _query.TransformUsing(Transformers.DistinctRootEntity).List<IUser>();
    return pagedReceiving;
}

但是这段代码会返回类似〜：

的查询

SELECT TOP(page_size) FROM AppUser left outer join UserPrinciples 
on AppUser.User_Id=UserPrinciples.User_ID 
ORDER BY UserPrinciples.UserName asc

并且这还不够好，因为我只需要每个user_id中的一条记录，而对于某些用户，使用此查询我可以获得多条记录，这就是问题所在。

任何人都可以帮忙吗？不确定是否需要任何其他细节

感谢和最好的问候

Answer 1

表示为没有分区的SQL

SELECT TOP(page_size) up.*, au.* from
  (SELECT UserName, Min(User_Id) as User_Id FROM UserPrinciples GROUP BY UserName) as x
LEFT JOIN
  UserPrinciples up ON x.UserName = up.UserName AND x.User_Id = up.User_Id
LEFT JOIN
  AppUser au ON  au.User_Id = up.User_Id

翻译成linq的

应该是符合条件的：

var y = from up1 in session.Query<Employment>()
        group up1 by up1.Name into g
        select new { Name = g.Key, UserId = g.Min(x => x.Company.Id) } into f
        join up2 in session.Query<Employment>() on new { f.Name, f.UserId } equals new { up2.Name, UserId = up2.Company.Id }
        select new SomeDto
        {
            ProfileName = up2.Name,
            UserId = up2.User.Id,
            Name = up2.User.Name,
        };

var results = y.ToList();

将SQL查询转换为NHibernate查询

我在NHibernate中需要这个查询，使用paging：

我现在的相关代码是：

但是这段代码会返回类似〜：

1 个答案: