LINQ to SQL的加入问题 [英] LINQ to SQL Join issues

问题描述

我尝试使用下面的LINQ在我的代码到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() } ));

发生在第二个连接线（在上面整个查询3号线）的错误 - 我用有它，所以它只是加入了s.ID和pop.AccountID和完美的工作，但现在我介绍了另一起critieria（该syncno）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:

的类型$ b $表达式b中加入条款之一是不正确。键入
推断在调用
'群组加入失败

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

任何想法？一些注意事项：

Any ideas? Some notes:

1：'变量'syncNo是一个长期的，因为是在DB（BIGINT）的值。在DB的值可为空，所以我也尝试过多长时间？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是一个自定义类我做了，因为你可能已经猜到

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

谢谢

推荐答案

尽量指定相同的连接键的名字如：

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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