LINQ Aggregate with Multiple Conditions - Unexpected Results in C# 10
I'm using LINQ to aggregate data from a list of `Transaction` objects, and I'm working with some unexpected results... I want to sum the `Amount` property for transactions that are both `Completed` and have occurred within the last 30 days. Here's a simplified version of my `Transaction` class: ```csharp public class Transaction { public decimal Amount { get; set; } public bool IsCompleted { get; set; } public DateTime Date { get; set; } } ``` I have a list of transactions like this: ```csharp List<Transaction> transactions = new List<Transaction> { new Transaction { Amount = 100, IsCompleted = true, Date = DateTime.Now.AddDays(-10) }, new Transaction { Amount = 200, IsCompleted = false, Date = DateTime.Now.AddDays(-5) }, new Transaction { Amount = 150, IsCompleted = true, Date = DateTime.Now.AddDays(-40) }, new Transaction { Amount = 50, IsCompleted = true, Date = DateTime.Now.AddDays(-20) }, }; ``` Here’s the LINQ query I’m using to calculate the total: ```csharp var total = transactions .Where(t => t.IsCompleted && t.Date >= DateTime.Now.AddDays(-30)) .Sum(t => t.Amount); ``` The expected result should be 150 (100 + 50), but I'm getting 100 instead. I've verified that the transactions are being filtered correctly, but the sum doesn't seem to include all the completed transactions. Could it be that the scenario lies in how I'm checking the date condition? I've also considered whether the `DateTime` comparisons might be causing the question due to time components. Any insights on what might be going wrong here? I'm using .NET 6.0 and LINQ, and I’d appreciate any advice on best practices for this type of aggregation. This is for a web app running on Windows 10. Thanks for any help you can provide! I've been using Csharp for about a year now.