Linq 与 group by 加入

【问题标题】：Linq with group by joinLinq 与 group by 加入
【发布时间】：2015-04-04 07:17:52
【问题描述】：

如何在linq中编写如下sql join？

select Campaign.CampaignName, COUNT(*) as total
 from Campaign join CampaignAsset
 on CampaignAsset.CampaignId=Campaign.CampaignId 
where Campaign.UserProfileId=65 
 Group By Campaign.CampaignName

【问题讨论】：

标签： sql linq join

【解决方案1】：

试试这个：

        YourDatabaseName dataContext = new YourDatabaseName();

var result =  from c in dataContext.Campaign
              join ca in dataContext.CampaignAsset on c.CampaignId equals ca.CampaignId into j1
              from j2 in j1.DefaultIfEmpty()
              where c.UserProfileId = 65                  
              group j2 by c.CampaignName into grouped
              select new { CampaignName = grouped.Key, Count = grouped.Count() };

【讨论】：

感谢您的宝贵时间，但这给出了错误“c”在当前上下文中不存在。