c# – Linq-to-Entities Left JOIN
发布时间:2020-12-15 08:00:52 所属栏目:百科 来源:网络整理
导读:这是我的查询: from forum in Forums join post in Posts on forum equals post.Forum into postGroup from p in postGroup where p.ParentPostID==0 select new { forum.Title,forum.ForumID,LastPostTitle = p.Title,LastPostAddedDate = p.AddedDate }).
这是我的查询:
from forum in Forums join post in Posts on forum equals post.Forum into postGroup from p in postGroup where p.ParentPostID==0 select new { forum.Title,forum.ForumID,LastPostTitle = p.Title,LastPostAddedDate = p.AddedDate }).OrderBy(o=>o.ForumID) 目前,Join不是左连接,这意味着如果某个论坛没有属于它的帖子,则不会返回. UPDATE 结果集应该是这样的: ForumId | ForumTitle | LastPostTitle | LastPostAddedDate --------+------------+---------------+------------------ 4 | Sport | blabla | 12/4/2010 4 | Sport | blabla | 15/4/2010 6 | Games | blabla | 1/5/2010 7 | Flame | | 解决方法var allforums = from f in context.Fora.Include("Posts") select f; 此查询产生的结果与 var allForums = from f in context.Fora select new ForumPosts { Forum = f,Posts = context.Posts.Where(x=> x.ForumId == f.ForumId) (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |