Subsonic 3.0 左连接 [英] Subsonic 3.0 Left Join

问题描述

尝试使用 linq 在 subsonic 中进行左连接，但似乎不起作用，我遇到了一个大错误.

Trying to do a left join in subsonic using linq but it doesn't seem to work, I get a big error.

我很确定查询是正确的，因为我已经用对象和 Linq2Sql 做过几次了.

I'm pretty sure the query is correct as I've done it a few times with objects and Linq2Sql.

            var post = from p in Post.All()
                        join q in Quote.All() on p.ID equals q.PostID into pq
                        where p.ID == id.Value
                        from qt in pq.DefaultIfEmpty()
                        select new {p, qt};

似乎 subsonic 无法从左连接 linq 查询生成所需的 SQL.

It just seems subsonic isn't able to generate the required SQL from left join linq queries.

我在这里做错了吗?有解决办法吗?

Am I doing something wrong here? Is there a work around?

更新:我使用的是 subsonic 3.0.0.2，这是我尝试使用 subsonic 进行左连接时出现的错误

Update: I'm using subsonic 3.0.0.2 here is the error I get when I try a left join with subsonic

'System.Collections.Generic.IEnumerable1[GetAQuote.Post]' 类型的表达式不能用于方法类型 'System.Linq.IQueryable1[GetAQuote.Post]' 的参数'System.Linq.IQueryable1[<>f__AnonymousType22[GetAQuote.Post,System.Collections.Generic.IEnumerable1[GetAQuote.Quote]]] GroupJoin[Post,Quote,Int32,<>f__AnonymousType22](System.Linq.IQueryable1[GetAQuote.Post], System.Collections.Generic.IEnumerable1[GetAQuote.Quote], System.Linq.Expressions.Expression1[System.Func2[GetAQuote.Post,System.Int32]], System.Linq.Expressions.Expression1[System.Func2[GetAQuote].Quote,System.Int32]], System.Linq.Expressions.Expression1[System.Func3[GetAQuote.Post,System.Collections.Generic.IEnumerable1[GetAQuote.Quote],<>f__AnonymousType22[GetAQuote.Post,System.Collections.Generic.IEnumerable`1[GetAQuote.Quote]]]])'

Expression of type 'System.Collections.Generic.IEnumerable1[GetAQuote.Post]' cannot be used for parameter of type 'System.Linq.IQueryable1[GetAQuote.Post]' of method 'System.Linq.IQueryable1[<>f__AnonymousType22[GetAQuote.Post,System.Collections.Generic.IEnumerable1[GetAQuote.Quote]]] GroupJoin[Post,Quote,Int32,<>f__AnonymousType22](System.Linq.IQueryable1[GetAQuote.Post], System.Collections.Generic.IEnumerable1[GetAQuote.Quote], System.Linq.Expressions.Expression1[System.Func2[GetAQuote.Post,System.Int32]], System.Linq.Expressions.Expression1[System.Func2[GetAQuote.Quote,System.Int32]], System.Linq.Expressions.Expression1[System.Func3[GetAQuote.Post,System.Collections.Generic.IEnumerable1[GetAQuote.Quote],<>f__AnonymousType22[GetAQuote.Post,System.Collections.Generic.IEnumerable`1[GetAQuote.Quote]]]])'

推荐答案

我有一个用于 left join 的 fork，我将在接下来的几天内使用它 - 给我一周时间，我将推出另一个版本.

I have a fork for left join that I'll be pulling in the next few days - gimme a week and I'll push another release with this.

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