I would like to ask how to write a query, can help me?

This is my mongodb query statement:

db.buy_sell_points.aggregate([
    {
        $match: {
            "symbol": { $in: ['002597','600004'] }
        }
    },
    {
        $sort: {
            "modified_on": -1
        }
    },
    {
        $group: {
            _id: {
                "symbol": "$symbol",
                "period": "$period"
            },
            "TopModifiedOnDoc": { $first: "$$ROOT" }
        }
    },
    {
        $replaceRoot: { newRoot: "$TopModifiedOnDoc" }
    }
])

I have defined an entity BuySellPoint, but I don’t know how to write this query using MongoDB.Entities.

[dj-nitehawk]

using MongoDB.Driver;
using MongoDB.Driver.Linq;
using MongoDB.Entities;

await DB.InitAsync("test");

var seedData = new[]
{
    new BuySellPoint{ ID = "1", Period = "january", Symbol = "001", ModifiedOn = DateTime.UtcNow.AddDays(-2)},
    new BuySellPoint{ ID = "2", Period = "january", Symbol = "001", ModifiedOn = DateTime.UtcNow.AddDays(-1)},

    new BuySellPoint{ID = "3", Period = "february", Symbol = "001", ModifiedOn = DateTime.UtcNow.AddDays(-2)},
    new BuySellPoint{ID = "4", Period = "february", Symbol = "001", ModifiedOn = DateTime.UtcNow.AddDays(-1)}
};

await seedData.SaveAsync();

var symbols = new[] { "001", "002" };

var res = await DB
    .Queryable<BuySellPoint>()
    .Where(p => symbols.Contains(p.Symbol))
    .OrderByDescending(p => p.ModifiedOn)
    .GroupBy(p => new { p.Symbol, p.Period })
    .Select(g => g.First())
    .ToListAsync();

foreach (var r in res)
    Console.WriteLine($"top modified: {r.ID}");

//expected to print : 2 & 4

Console.ReadLine();

[Collection("buy_sell_points")]
public class BuySellPoint : Entity //, IModifiedOn
{
    [Field("symbol")]
    public string Symbol { get; set; }

    [Field("period")]
    public string Period { get; set; }

    [Field("modified_on")]
    public DateTime ModifiedOn { get; set; }
}

[lamjack]

Perfect, It’s works for me. Thanks very much for your help.