Converting sql to LINQ C#

Try something like this

   class Program
    {

        static void Main(string[] args)
        {
            int CURRENT_TIMESTAMP = 123;

            List<CONFIGURATION_LOG> logs = new List<CONFIGURATION_LOG>();
            var results = logs.Where(x => (x.APP_ID == 173) && (x.ROW_LST_UPD_TS >= CURRENT_TIMESTAMP - 7))
                .OrderByDescending(x => x.ROW_LST_UPD_TS)
                .GroupBy(x => x.SETTING_NAME)
                .Select(x => x.FirstOrDefault())
                .Select(x => new
                {
                    setting_name = x.SETTING_NAME,
                    setting_value = x.SETTING_VALUE,
                    row_lst_upd_ts = x.ROW_LST_UPD_TS,
                    machine_name = x.MACHINE_NAME,
                    row_lst_upd_uid = x.ROW_LST_UPD_UID
                }).ToList();

        }
    }
    public class EVENT_MGT
    {
        CONFIGURATION_LOG CONFIGURATION_LOG { get; set; } 
    }
    public class CONFIGURATION_LOG
    {
        public string SETTING_NAME { get; set; }
        public string SETTING_VALUE { get; set; }
        public int ROW_LST_UPD_TS { get; set; }
        public string MACHINE_NAME { get; set; }
        public string ROW_LST_UPD_UID { get; set; }
        public int APP_ID { get; set; }
    }

You give the loss information. Maybe you want one thing such as this keywork: Entity Framework. Follow this link;

Besides, I have an idea for optimize use of call SQL query command to get data from a table includes columns with image datatype using C# without Entity Framework in 3 steps with a small example:

Step 0: (default) Create a new table. This is my table TBUsers:

CREATE TABLE [dbo].[TBUsers]
(
    [STT] [BIGINT] IDENTITY(1,1) NOT NULL,
    [HoTen] [NVARCHAR](MAX) NOT NULL,
    [MaSo] [NVARCHAR](50) NOT NULL,
    [MatKhau] [NVARCHAR](MAX) NOT NULL,
    [KhoaLop] [NVARCHAR](MAX) NOT NULL,
    [MaTheGui] [NVARCHAR](50) NOT NULL,
    [PhanQuyen] [INT] NOT NULL,
    [ChoPhepHoatDong] [BIT] NOT NULL,
    [NguoiThem] [NVARCHAR](MAX) NOT NULL,
    [NgayThem] [DATETIME] NOT NULL,
    [SoDuKhaDung] [BIGINT] NOT NULL,
    [DangGui] [BIT] NOT NULL,
    [TruyCapLanCuoi] [DATETIME] NULL,
    [ThoiGianGuiCuoi] [DATETIME] NULL,
    [HinhAnh] [IMAGE] NULL,
    [DonGia] [BIGINT] NULL,

    CONSTRAINT [PK_TBUsers] 
        PRIMARY KEY CLUSTERED ([MaTheGui] ASC)
                    WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, 
                          IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, 
                          ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO

Step 1: create a new class that corresponds to the table above and create 2 constructors, Users:

    public class Users
    {
        public Users()
        { }

        public Users(object sTT, object hoTen, object maSo, object matKhau, object khoaLop, object maTheGui, object phanQuyen, object choPhepHoatDong,
            object nguoiThem, object ngayThem, object soDuKhaDung, object dangGui, object truyCapLanCuoi, object thoiGianGuiCuoi, object hinhAnh,object donGia)
        {
            STT = sTT.ToString();
            HoTen = hoTen.ToString();
            MaSo = maSo.ToString();
            MatKhau = matKhau.ToString();
            KhoaLop = khoaLop.ToString();
            MaTheGui = maTheGui.ToString();
            PhanQuyen = phanQuyen.ToString();
            ChoPhepHoatDong = choPhepHoatDong.ToString();
            NguoiThem = nguoiThem.ToString();
            NgayThem = ngayThem.ToString();
            SoDuKhaDung = soDuKhaDung.ToString();
            DangGui = dangGui.ToString();
            TruyCapLanCuoi = truyCapLanCuoi.ToString();
            ThoiGianGuiCuoi = thoiGianGuiCuoi.ToString();

            HinhAnh = hinhAnh==System.DBNull.Value?null: (byte[])hinhAnh;
            DonGia = donGia.ToString();
            Color = (bool)choPhepHoatDong;
        }

        public string STT { get; set; }
        public string HoTen { get; set; }
        public string MaSo { get; set; }
        public string MatKhau { get; set; }
        public string KhoaLop { get; set; }
        public string MaTheGui { get; set; }
        public string PhanQuyen { get; set; }
        public string ChoPhepHoatDong { get; set; }
        public string NguoiThem { get; set; }
        public string NgayThem { get; set; }
        public string SoDuKhaDung { get; set; }
        public string DangGui { get; set; }
        public string TruyCapLanCuoi { get; set; }
        public string ThoiGianGuiCuoi { get; set; }
        public byte[] HinhAnh { get; set; }
        public string DonGia { get; set; }
        public bool Color { get; set; }
    }
}

Step 2: Get Users from database with the ParseUser function:

    public static Users ParseUser(DataRow row)
    {
        var stt = row["STT"];
        var hoTen = row["HoTen"];
        var maSo = row["MaSo"];
        var matKhau = row["MatKhau"];
        var khoaLop = row["KhoaLop"];
        var maTheGui = row["MaTheGui"];
        var phanQuyen = row["PhanQuyen"];
        var choPhepHoatDong = row["ChoPhepHoatDong"];
        var nguoiThem = row["ChoPhepHoatDong"];
        var ngayThem = row["ChoPhepHoatDong"];
        var soDuKhaDung = row["SoDuKhaDung"];
        var dangGui = row["DangGui"];
        var truyCapLanCuoi = row["TruyCapLanCuoi"];
        var guiLanCuoi = row["ThoiGianGuiCuoi"];
        var hinhAnh = row["HinhAnh"] == System.DBNull.Value ? null : row["HinhAnh"];
        var donGia = row["DonGia"];

        return new Users(stt, hoTen, maSo, matKhau, khoaLop, maTheGui, phanQuyen, choPhepHoatDong, nguoiThem, ngayThem, soDuKhaDung, dangGui,
            truyCapLanCuoi, guiLanCuoi, hinhAnh, donGia);
    }

Step 3: Easily take an instance of Users class with ParseUser function:

Users user = ParseUser(sqlUtility.GetDataTable($"SELECT * FROM [dbo].[TBUsers] WHERE MaSo = 'xxx' AND ChoPhepHoatDong=1;").Rows[0]);

Similarly, you can create a class to retrieve the entire Users using any collection such as List<User> or IEnumerable<User>. You can use LinQ to query with this data.

Thanks to jdweng, I figured out how to get exactly what I need:

var results = config_log.Where(x => x.AppId == 173)
                                    .OrderByDescending(x => x.RowLstUpdTs).ToList()
                                    .GroupBy(x => x.SettingName )
                                    .Select(x => new
                                    { 
                                        setting_name = x.Select(y => y.SettingName).FirstOrDefault(),
                                        setting_value = x.Select(y => y.SettingValue).FirstOrDefault(),
                                        row_lst_upd_ts = x.Select(y => y.RowLstUpdTs).FirstOrDefault(),
                                        machine_name =  x.Select(y => y.MachineName).FirstOrDefault(),
                                        row_lst_upd_uid = x.Select(y => y.RowLstUpdUid).FirstOrDefault()
                                    }).ToList();