我需要unoin两个查询并且结合group by之后,但抛出“必须可节点”的异常。在下面的示例代码是:Group by union throw“必须可节点”例外
public class ForumPost
{
public int ForumPostId { get; set; }
public string Message { get; set; }
public bool Deleted { get; set; }
public int ForumTopicId { get; set; }
public virtual ForumTopic ForumTopic { get; set; }
}
var query1 = _dbContext.ForumPosts
.Where(e => e.Deleted == true);
var query2 = _dbContext.ForumPosts
.Where(e => e.Deleted == false);
var query = query1.Union(query2);
var list = query.GroupBy(e => e.ForumTopicId)
.Select(group => new
{
group.Key,
Total = group.Count()
}).Take(10)
.ToList();
有没有人遇到过这个问题?
在内存分组工作? – Tseng
@Tseng:内存中的作品! –