在c#中从数据库中选择单个值(当表有多个相似值时

using System;
using System.Data.SqlClient;

class Program
{
    static void Main()
    {
        string connectionString = "Data Source=YourServerName;Initial Catalog=YourDatabaseName;User ID=YourUsername;Password=YourPassword";
        string query = "SELECT columnName FROM tableName WHERE condition";

        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();

            using (SqlCommand command = new SqlCommand(query, connection))
            {
                object result = command.ExecuteScalar();

                if (result != null)
                {
                    string value = result.ToString();
                    Console.WriteLine("Selected value: " + value);
                }
                else
                {
                    Console.WriteLine("No value found.");
                }
            }
        }
    }
}