DataAccessLayer.DataBase.GetLikedByUser C# (CSharp) Метод

        public IEnumerable<Guid> GetLikedByUser(string modelName)
        {
            var account = GetAccountByLogin(modelName, true);
            var accountId = account.Id;
            var queryString =
                "SELECT (postid) " +
                "FROM [dbo].Likes " +
                "WHERE accountid = @accountid;";
            using (SqlConnection connection = new SqlConnection(_connectionString))
            {
                List<Guid> _list;
                var command = new SqlCommand(queryString, connection);
                command.Parameters.AddWithValue("accountid", accountId);
                connection.Open();

                var reader = command.ExecuteReader();
                _list = new List<Guid>();

                while (reader.Read())
                    _list.Add((Guid)reader[0]);

                return _list;
            }
        }