如果为空，则返回C#中的SELECT语句(Visual Studio)

using System;
using System.Data.SqlClient;

class Program
{
    static void Main()
    {
        string connectionString = "Data Source=(local);Initial Catalog=YourDatabase;Integrated Security=True";
        string selectQuery = "SELECT * FROM YourTable";

        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            SqlCommand command = new SqlCommand(selectQuery, connection);
            connection.Open();

            SqlDataReader reader = command.ExecuteReader();
            while (reader.Read())
            {
                // 处理每一行数据
                int id = (int)reader["ID"];
                string name = (string)reader["Name"];
                DateTime dateOfBirth = (DateTime)reader["DateOfBirth"];

                Console.WriteLine($"ID: {id}, Name: {name}, Date of Birth: {dateOfBirth}");
            }

            reader.Close();
        }
    }
}