Как получить значение ид зная один из параметров записи?

Question

[Дмитрий Королев]

Как узнать ид записи зная переменную в записи?

command = new SqlCommand("SELECT * FROM [Recent] WHERE [LibraryId] = @LibraryId", sqlConnection);//не знаю
            byte _id = 0;
            try
            {
                _id = Convert.ToByte(command.ExecuteScalar());
            }
            catch (Exception exc)
            {
                Console.WriteLine(exc.Message + "  2   " + exc.Source);
                _id = 0;
            }
            finally
            {
                if (_id != 0)
                {
                    command = new SqlCommand("DELETE FROM [Recent] WHERE [Id] = @Id", sqlConnection);
                    command.Parameters.AddWithValue("Id", _id);
                    await command.ExecuteNonQueryAsync();
                }
            }

Answer 1

[Johnny Gat]

command = new SqlCommand("SELECT [Id] FROM [Recent] WHERE [LibraryId] = @LibraryId", sqlConnection);
command.Parameters.AddWithValue("LibraryId", вашеЗначение);

Comments

[Дмитрий Королев]

Правильно я написал?
1.

command = new SqlCommand("SELECT [Id] FROM [Recent] WHERE [LibraryId] = @LibraryId", sqlConnection);
            byte _id = 0;
            command.Parameters.AddWithValue("LibraryId", library);
            SqlDataReader sqlReader = null;
            try
            {
                sqlReader = await command.ExecuteReaderAsync();
                while (await sqlReader.ReadAsync())
                {
                    title = Convert.ToString(sqlReader["Id"]);
                }
            }
            catch (Exception exc)
            {
                Console.WriteLine(exc.Message + "    " + exc.Source);
                _id = 0;
            }
            finally
            {
                if (sqlReader != null)
                    sqlReader.Close();
                if (_id != 0)
                {
                    command = new SqlCommand("DELETE FROM [Recent] WHERE [Id] = @Id", sqlConnection);
                    command.Parameters.AddWithValue("Id", _id);
                    await command.ExecuteNonQueryAsync();
                }
            }

А этот код будет работать?
2.

command = new SqlCommand("SELECT [Id] FROM [Recent] WHERE [LibraryId] = @LibraryId", sqlConnection);
            byte _id = 0;
            command.Parameters.AddWithValue("LibraryId", library);
            try
            {
                _id = Convert.ToByte(command.ExecuteScalar());
            }
            catch (Exception exc)
            {
                Console.WriteLine(exc.Message + "     " + exc.Source);
                _id = 0;
            }
            finally
            {
                if (_id != 0)
                {
                    command = new SqlCommand("DELETE FROM [Recent] WHERE [Id] = @Id", sqlConnection);
                    command.Parameters.AddWithValue("Id", _id);
                    await command.ExecuteNonQueryAsync();
                }
            }

что можно получить скаляром в этом случае?

[Johnny Gat]

Дмитрий Королев, я бы вообще написал:

command = new SqlCommand("DELETE FROM [Recent] WHERE [LibraryId] = @LibraryId", sqlConnection);
command.Parameters.AddWithValue("LibraryId", library);
command.ExecuteNonQuery();

что можно получить скаляром в этом случае?

https://msdn.microsoft.com/ru-ru/library/system.da...