nHibernate 计算子查询中的行数
我怎样才能在nHibernate中做这样的事情：
select count(*)
from (subquery)
这是一个相当简单的SQL查询，但在nHibernate中解决方案并不那么明显。一个明显的解决方案是：
var rowcount = Session.QueryOver<Entity>()
.Select(Projections.Alias(Projections.Count(Projections.SubQuery(detachedQuery)), "count"))
.FutureValue<int>();
但是，这会导致 ArgumentOutOfRangeException：
Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
这个所以答案对我不起作用，因为我有一个更复杂的分组。 我的问题源自一个较早的问题，我尝试使用ToRowCountQuery，但该函数会从查询中剥离分组。
How can I do something like this in nHibernate:
select count(*)
from (subquery)
It is a rather simple query in SQL, but the solution is not so obvious in nHibernate. An obvious solution would be something along the line of:
var rowcount = Session.QueryOver<Entity>()
.Select(Projections.Alias(Projections.Count(Projections.SubQuery(detachedQuery)), "count"))
.FutureValue<int>();
However, this results in an ArgumentOutOfRangeException:
Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
This SO answer doesn't work for me, as I have a more complex grouping.
My question originates from an earlier question where I tried to use ToRowCountQuery, but that function strips groupings form the query.
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一旦您有了
会话，您就可以Once you have a
session, you could我发现 Ayende 的一篇旧帖子给了我一个解决方案（计算分页数据）。
我按照该帖子中的描述创建了自己的方言，并将
rowcount函数添加到我的分页查询中。很快，我就在对数据库的单个查询中获得了行计数。I found an old post by Ayende which gave me a solution (Counting paged data).
I created my own dialect as described in that post and added the
rowcountfunction to my paged query. And presto, I got my rowcount in a single query to the database.