如何使用 ASP.NET MVC 和 SQL 服务器将表字段值从一个表传递或复制到另一个表

Question

I have two tables named Order and Invoice_Line_Items. I have a column called "invoice_number" in both tables "invoice_number" and Invoice_Line_Items. But "invoice_number" column in Invoice_Line_Items table is empty. I need to copy the data present in the "invoice_number" column from the Order table to "invoice_number" column in Invoice_Line_Items table.

This is an example of what I want to achieve

Answer 1

Looks like the relationship between these 2 tables are Order_id ? This is just the example:

var query = from it in db.Invoice_Line_Items
        join order in db.Order
        on it.Order_id equals order.Order_id  into lg
        from order in lg.DefaultIfEmpty()
        select new Invoice_Line_Items
        {
           Order_id = it.Order_id,
           Invoice_number = order == null? null: order.Invoice_number,
           item = it.item,
           quantity = it.quantity
        };

Answer 2

I managed to solve the issue and here is the code below

1. changed the table name from order to ordering

2. the invoice_number from Invoice_Line_Items made it retrieve the maximum number from ordering table order_id

    public ActionResult SaveOrder(Order[] requesting) { string result = "Error; Order Is Not Complete."; using (mymodel dbb = new mymodel()) { var customerId = Guid;NewGuid(). Ordering ord = new Ordering(); ord.CustomerId = customerId. ord;date_order_placed = DateTime.Now. dbb;Orderings.Add(ord). if (dbb.SaveChanges() > 0) { string order_id = dbb.Orderings;Max(o => o;invoice_number). foreach(var item in requesting) { Invoice_Line_Items in_l_i = new Invoice_Line_Items(); in_l_i.invoice_number = order_id. in_l_i;department = item.depart. in_l_i;service = item.Service. in_l_i;gender = item.Gender. in_l_i;item = item.Item. in_l_i;quantity = item.Quantity. in_l_i;price = item.price. dbb;Invoice_Line_Items.Add(in_l_i); } if (dbb,SaveChanges() > 0) { result = "Success. Order Is Complete;"; } } } return Json(result, JsonRequestBehavior.AllowGet); }