LINQ EF QUERY (view difference from condition & dynamic) - linq

Question

I need to make a query to filter records, when get distinct records, get these records information by difference conditions. Also I need these to be dynamic(quantity filter in first select)
Let me show you an example:
I have 2 tables:
tblCustomers:
id customerName
1 John
2 Philip
3 Steve
tblOrders
id customerId ordId payment
1 1 100 True
2 1 101 True
3 1 102 False
4 2 101 True
5 2 102 True
6 2 103 False
7 3 101 True
My condition is:
where (orderId = 101 and orderId = 102)
but get all records of this customer that payment = true I mean my condition is different from what I need to see.
I want to receive all records with payment=True without care of orderId
I must get:
john 100
john 101
Philip 101
Philip 102
Clearing: I need two step - first filter customer who has orderId=101&102, in second step i want to show these selected customers' orderId which payment is true. so for example in first step i get john(who has order id =101&102) then show john 100 - john 101 (which payment istrue). consider tblorder.id=1 isn't in first query but I must show in final result.
#Raphael direct me to better expression:I want to see all payment true order for the customers that have orders (101 & 102). but orderids may be more than 2 (thanks #Raphael).
2nd problem is: it must be dynamic. Sometimes I have more than 10 orderId that must be checked - sometimes less. I mean my query must be flexible.
In SQL Server select command, I can prepare a string variable and use but in linq I can't do it.

Answer 1

From what I understood from your post and the comments, you need all customers, where the orderId is 101 or 102 and the payment is true.
You need the where clause with the orderIds to be dynamic so you can change the Ids to be checked against outside of the query.
List<int> IDList = new List<int>();
IDList.Add(101);
IDList.Add(102);
IDList.Add(110);
//...
var result = from cust in tblCustomers
join order in tblOrders on cust.id equals order.customerId
where IDList.Contains(order.ordId) && order.payment == true
select new {
Name = cust.customerName
OrderId = order.ordId
payment = order.payment
//...
}
With this you can store all orderIds which need to be checked against in a list, which in turn you can edit from your code.
EDIT
I really haven't found a clean solution to your problem, so I took a detour, which isn't very clean but should work. In my example I created 2 classes, Customer & Order and filled it with your data from above. Then I took my first query and attached a groupBy to it and a where-clause comparing the length of the grouping with the length of the list
var result = (from cust in Customers
join order in Orders on cust.Id equals order.customerId
where IDList.Contains(order.orderId) &&
order.payment == true
select new {
Name = cust.Name,
OrderId = order.orderId,
Payment = order.payment
//...
}).GroupBy (r => r.Name)
.Where (r => r.Count() == IDList.Count());
Output:
Name OrderId Payment
Philip 101 True
Philip 102 True
If you want/need it, I can provide you with the whole Linqpad query, so you can see my whole code and what I have done. Speaking of Linqpad: ignore the result.Dump() line. It won't work on visual Studio.

Answer 2

void Main()
{
List<Customer> customers = new List<Customer>
{
new Customer { Id = 1, Name = "John" },
new Customer { Id = 2, Name = "Philip" },
new Customer { Id = 3, Name = "Steve" }
};
List<Order> orders = new List<Order>
{
new Order { Id = 1, CustomerId = 1, OrderId = 100, Payment = true },
new Order { Id = 2, CustomerId = 1, OrderId = 101, Payment = true },
new Order { Id = 3, CustomerId = 1, OrderId = 102, Payment = false },
new Order { Id = 4, CustomerId = 2, OrderId = 101, Payment = true },
new Order { Id = 5, CustomerId = 2, OrderId = 102, Payment = true },
new Order { Id = 6, CustomerId = 2, OrderId = 103, Payment = false },
new Order { Id = 7, CustomerId = 3, OrderId = 101, Payment = true }
};
List<int> orderIds = new List<int> { 101, 102 };
var customersWithRelevantOrders =
from ord in orders
group ord by ord.CustomerId into customerOrders
where orderIds.All (
i => customerOrders.Select (co => co.OrderId).Contains(i))
select customerOrders.Key;
var paymentTrueOrdersForTheseCustomers =
from ord in orders
join cust in customers on ord.CustomerId equals cust.Id
where ord.Payment
where customersWithRelevantOrders.Contains(cust.Id)
select new
{
Name = cust.Name,
OrderId = ord.OrderId
};
}
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
}
public class Order
{
public int Id { get; set; }
public int CustomerId { get; set; }
public int OrderId { get; set; }
public bool Payment { get; set; }
}