我如何在 EF Core 3.1 中的多个表上使用 Linq 表达式进行连接

问题描述

我有以下 5 个模型。我想在我的 ASP Core API 应用程序中使用 LINQ 将它们加入和分组。 我想加入我所有的 JournalVoucher、PurchaseInvoice 和 SaleInvoice 来计算一个项目的项目输入和输出以及剩余数量。请帮助我以最佳实践编写 LINQ 查询，

  <Layout style={{ minHeight: "100vh" }}>
    <Header>Header</Header>
    <Content>Content</Content>
    <Footer>Footer</Footer>
  </Layout>

采购发票表

      public partial class JournalVoucher : BaseEntity
      {
          //......
         public DateTime VoucherDate{ get; set; }
         public ICollection<Invoice> Invoices { get; set; }
         public ICollection<PurchaseInvoice> PurchaseInvoices { get; set; }            
      }         

销售发票表

               public partial class PurchaseInvoice : BaseEntity
               {
                   //...

                   public int Type{ get; set; }
                   public JournalVoucher JournalVoucher { get; set; }
                   public ICollection<PurchaseInvoiceLine> PurchaseInvoiceLines { get; set; }

               }

             public partial class PurchaseInvoiceLine : BaseEntity
             {
               //....
              public int ItemId { get; set; }
              public int UnitId { get; set; }
              public decimal Quantity { get; set; }
              public decimal discount { get; set; }
              public decimal Tax { get; set; }
              public PurchaseInvoice PurchaseInvoice { get; set; } 
             }

我的视图模型

  public partial class SaleInvoice : BaseEntity
               {
                   //...
                   public int Type{ get; set; }
                   public JournalVoucher JournalVoucher { get; set; }
                   public ICollection<SaleInvoiceLine> SaleInvoiceLines { get; set; }

               }

             public partial class SaleInvoiceLine : BaseEntity
             {
               //....
              public int ItemId { get; set; }
              public int UnitId { get; set; }
              public decimal Quantity { get; set; }
              public decimal discount { get; set; }
              public decimal Tax { get; set; }
              public SaleInvoice SaleInvoice { get; set; } 
             }

现在我想要通过使用 group by 连接这五个表来获得以下结果数据。

销售发票数量 = QuantityOut

采购发票数量= QuantityIn

   public class ItemUsedInPurchaseAndInvoiceviewmodel
   {

    public int ItemId { get; set; }
    public int UnitId { get; set; }
    public decimal UnitPrice { get; set; }
    public decimal discount { get; set; }
    public decimal Tax { get; set; }
    public decimal QuantityIn { get; set; }
    public decimal QuantityOut { get; set; }
    public DateTime VoucherDate{ get; set; }
    public int Type{ get; set; }
    public decimal TotalPriceIn => ((UnitPrice * QuantityIn - discount) + Tax);
    public decimal TotalPriceOut => ((UnitPrice * QuantityOut - discount) + Tax);
    public decimal TotalRemain => QuantityIn - QuantityOut;

}

解决方法

你可以做这样的例子：

m=mysql -p $password -h $host -u$user #you can also inline it of course 
for i in `$m -e "show processlist" | awk '/$anySearchString/ {print $1}'`; do $m -e "call mysql.rds_kill($i);"; done