public class UserAppraisal public int UserId get; set; public string UserName get; set; public string Sex get; set; public int AppraisalBase get; set; pu

public class UserAppraisal { public int UserId { get; set; } public string UserName { get; set; } public string Sex { get; set; } public int? AppraisalBase { get; set; } public string BaseType { get; set; } public int? IsDel { get; set; }

public static List<UserAppraisal> GetListJoinApp()
{
    List<UserAppraisal> appraisalBasesList = new List<UserAppraisal>(); // 创建一个列表用于存储查询结果
    string server = "localhost";
    string database = "todoapp";
    string username = "root";
    string password = "root";
    string querySql = "SELECT u.UserId,u.UserName,u.Sex,a.AppraisalBase,a.BaseType,u.IsDel FROM users u LEFT JOIN appraisalbases a ON u.BaseTypeId=a.Id";

    using (MySqlConnection connection = new MySqlConnection($"server={server}; database={database}; username={username}; password={password}"))
    {
        connection.Open();

        using (MySqlCommand command = new MySqlCommand(querySql, connection))
        {
            using (MySqlDataReader reader = command.ExecuteReader())
            {
                while (reader.Read())
                {
                    int userId = reader.GetInt32("UserId");
                    string userName = reader.GetString("UserName");
                    string sex = reader.GetString("Sex");
                    int? appraisalBase = reader.IsDBNull(reader.GetOrdinal("AppraisalBase")) ? null : reader.GetInt32("AppraisalBase");
                    string baseType = reader.IsDBNull(reader.GetOrdinal("BaseType")) ? null : reader.GetString("BaseType");
                    int? isDel = reader.GetInt32("IsDel");

                    UserAppraisal appraisal = new UserAppraisal()
                    {
                        UserId = userId,
                        UserName = userName,
                        Sex = sex,
                        AppraisalBase = appraisalBase,
                        BaseType = baseType,
                        IsDel = isDel
                    };

                    appraisalBasesList.Add(appraisal);
                }
            }
        }
    }

    return appraisalBasesList;
}