Get sum of two columns in one LINQ query

Question

let\'s say that I have a table called Items (ID int, Done int, Total int)

I can do it by two queries:

int total = m.Items.Sum(p=>p.Total)
int done         


        

Answer 1

Using the language support for tuples introduced in C# 7.0 you can solve this using the following LINQ expression:

var itemSums = m.Items.Aggregate((Total: 0, Done: 0), (sums, item) => (sums.Total + item.Total, sums.Done + item.Done));

Full code sample:

var m = new
{
    Items = new[]
    {
        new { Total = 10, Done = 1 },
        new { Total = 10, Done = 1 },
        new { Total = 10, Done = 1 },
        new { Total = 10, Done = 1 },
        new { Total = 10, Done = 1 },
    },
};

var itemSums = m.Items.Aggregate((Total: 0, Done: 0), (sums, item) => (sums.Total + item.Total, sums.Done + item.Done));

Console.WriteLine($"Sum of Total: {itemSums.Total}, Sum of Done: {itemSums.Done}");