I have the following model where I'd like to get the sum of all OrderTotalItems for all Orders of a Customer where the OrderTotalType (Enumeration) is "total" or 99:
public class Customer
{
...
public ICollection<Order> Orders { get; set; } = new Collection<Order>();
}
public class Order
{
...
public ICollection<OrderTotalItem> OrderTotalItems { get; set; } = new Collection<OrderTotalItem>();
}
public class OrderTotalItem
{
[Required]
public int Id { get; set; }
[Required]
[Column(TypeName = "decimal(10, 4)")]
public decimal Value { get; set; }
[Required]
public OrderTotalType Type { get; set; }
}
I am building a CustomerAdminDTO to include all relevant data of a customer for the admin client:
public class CustomerAdminDto
{
public int Id { get; set; }
public string UserId { get; set; }
public Gender Gender { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string VATId { get; set; } = "";
public bool VATIdValid { get; set; } = false;
public DateTime Added { get; set; }
public DateTime LastModified { get; set; }
public decimal OrdersTotal { get; set; }
public CustomerStatusShortDto CustomerStatus { get; set; }
public CustomerAddressDto CustomerAddress { get; set; }
public CustomerAddressDto BillingAddress { get; set; }
public ICollection<OrderListShortDto> Orders { get; set; }
}
In my data service I fill the DTO like that
var customerAdmin = await _context.Customers
.Include(x => x.Addresses)
.Include(x => x.CustomerStatus)
.Include(x => x.Orders)
.ThenInclude(x => x.OrderTotalItems)
.Where(x => x.UserId == userid)
.Select(customer => new CustomerAdminDto
{
Id = customer.Id,
UserId = customer.UserId,
Gender = customer.Gender,
FirstName = customer.FirstName,
LastName = customer.LastName,
VATId = customer.VATId,
VATIdValid = customer.VATIdValid,
Added = customer.Added,
LastModified = customer.LastModified,
OrdersTotal = customer.Orders.Sum(x => x.OrderTotalItems
.Where(x => x.Type == Enums.OrderTotalType.Total)
.Sum(x => x.Value)),
CustomerStatus = new CustomerStatusShortDto
{
Id = customer.CustomerStatus.Id,
Name = customer.CustomerStatus.Name,
},
...
}
.FirstOrDefaultAsync();
where everything works, except the OrdersTotal.
API compiles fine but throws the following error at runtime:
Microsoft.Data.SqlClient.SqlException (0x80131904): Cannot perform an aggregate function on an expression containing an aggregate or a subquery.
Thanks for your hints!
Cannot perform an aggregate function on an expression containing an aggregate or a subquery.
This error in SQL server means that you tried to call aggregation function ( customer.Orders.Sum()
in your case) on other expression that contains aggregation function ( .Sum(x => x.Value)
in your case). In order to avoid this you can simplify your LINQ expression for OrdersTotal
:
OrdersTotal = customer.Orders.SelectMany(o => o.OrderTotalItems).Where(x => x.Type == Enums.OrderTotalType.Total).Sum(x => x.Value)
There is only one aggregation here so it should work fine
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