使用LINQ减去表中的列

using System;
using System.Linq;
using System.Data.SqlClient;

namespace LinqExample
{
    class Program
    {
        static void Main(string[] args)
        {
            // 建立与数据库的连接
            string connectionString = "your_connection_string";
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();

                // 创建LINQ查询对象
                var query = from row in connection.Table
                            select new
                            {
                                Column1 = row.Column1,
                                Column2 = row.Column2 - row.Column3
                            };

                // 执行查询
                var result = query.ToList();

                // 输出结果
                foreach (var item in result)
                {
                    Console.WriteLine("Column1: {0}, Column2: {1}", item.Column1, item.Column2);
                }
            }
        }
    }
}