LINQ to SQL 连接问题

问题描述

我正在尝试在我的代码中使用以下 LINQ to SQL:

I'm trying to use the following LINQ to SQL in my code:

  (from s in dc.Accounts 
  join purchases in dc.Transactions on s.AccID equals purchases.Account into pu
  join pop in dc.POPTransactions on new { s.ID, syncNo } equals new {AccId = pop.AccountID, SyncNo = pop.SyncNo } into po
  where s.AccID == ID && s.Customer == false
  select new AccsandPurchase { acc = s, purchases = pu.ToList(), pop = po.ToList() } ));

错误发生在第二个连接行(上面整个查询中的第 3 行) - 我曾经有它，所以它只是在 s.ID 和 pop.AccountID 上连接，效果很好，但现在我引入了另一个连接标准(同步)我收到以下错误:

The error happens on the second join line (3rd line in the whole query above) - I used to have it so it just joined on s.ID and pop.AccountID and that worked perfect, but now I introduced another join critieria (the syncno) I get the following error:

"中的表达式之一的类型join 子句不正确.类型调用中的推理失败'GroupJoin'"

"The type of one of the expressions in the join clause is incorrect. Type inference failed in the call to 'GroupJoin'"

有什么想法吗?一些注意事项:

Any ideas? Some notes:

1: '变量'syncNo' 是一个长整数，与数据库中的值 (bigint) 一样.数据库中的值可以为空，所以我也试过长?"作为变量类型

1: 'the variable 'syncNo' is a long, as is the value in the DB (bigint). The value in the db is nullable so I've also tried "long?" as the variable type

2:AccsandPurchase 是我制作的一个自定义类，你大概可以猜到

2: AccsandPurchase is a custom class I made, as you can probably guess

谢谢

推荐答案

尝试指定相同的连接键名称，例如

Try to specify the same join key names e.g.

join pop in dc.POPTransactions on new { Key1 = s.ID, Key2 = syncNo } equals new {Key1 = pop.AccountID, Key2 = pop.SyncNo }

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