LINQ聚合/ SUM分组问题

Question

我在将传统SQL聚合查询转换为LINQ时遇到困难。基本数据转储的工作原理是这样：

Dim result = 
    (From i As Models.InvoiceDetail In Data.InvoiceDetails.GetAll 
    Join ih As Models.InvoiceHeader In Data.InvoiceHeaders.GetAll On i.InvoiceHeaderID Equals ih.ID 
    Join p As Models.Product In Data.Products.GetAll On i.ProductID Equals p.ID 
    Join pg As Models.ProductGroup In Data.ProductGroups.GetAll On p.ProductGroupID Equals pg.ID 
    Join gl As Models.GLAccount In Data.GLAccounts.GetAll On pg.GLAccountSellID Equals gl.ID 
    Where (gl.ID = GLID) 
    Select ih.Period,i.ExtendedValue) 

我需要真正地走出什么是ih.Period（从1到12的值）和i.ExtendedValue对应的总价值。当我尝试将ih分组时，我收到有关我超出作用域/上下文的错误，并且我不确定还有什么其他解决方法。

Answer 1

尝试将其分解为两个不同的查询以简化操作。例如：

From result In 
    (From i As Models.InvoiceDetail In Data.InvoiceDetails.GetAll 
    Join ih As Models.InvoiceHeader In Data.InvoiceHeaders.GetAll On i.InvoiceHeaderID Equals ih.ID 
    Join p As Models.Product In Data.Products.GetAll On i.ProductID Equals p.ID 
    Join pg As Models.ProductGroup In Data.ProductGroups.GetAll On p.ProductGroupID Equals pg.ID 
    Join gl As Models.GLAccount In Data.GLAccounts.GetAll On pg.GLAccountSellID Equals gl.ID 
    Where (gl.ID = GLID) And (ih.FinancialYear = FinancialYear) 
    Select ih.Period, i.ExtendedValue) 
Group By result.Period Into Sum(result.ExtendedValue)