将SQL请求转换为linq查询c# (左外部连接和内连接)

var query = from customer in customers
            join order in orders
            on customer.CustomerID equals order.CustomerID into customerOrders
            from co in customerOrders.DefaultIfEmpty()
            select new { CustomerName = customer.CustomerName, OrderID = co?.OrderID };

foreach (var result in query)
{
    Console.WriteLine($"Customer: {result.CustomerName}, OrderID: {result.OrderID}");
}

var query = from customer in customers
            join order in orders
            on customer.CustomerID equals order.CustomerID
            select new { CustomerName = customer.CustomerName, OrderID = order.OrderID };

foreach (var result in query)
{
    Console.WriteLine($"Customer: {result.CustomerName}, OrderID: {result.OrderID}");
}