C# 查询一个值方法ExecuteScalar()

需要从SQL查询中返回一个值，如表中记录数。可以使用ExecuteScalar()方法，这个方法只返回一个值。如下边控制台应用程序代码所示：

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

namespace ExecuteScalar
{
    class Program
    {
        static void Main(string[] args)
        {
            SqlConnection thisConnection = new SqlConnection(
     @"Data Source=scott;Initial Catalog=northwind;Persist Security Info=True;User ID=sa;Password=sa123");

            thisConnection.Open();

            SqlCommand thisCommand = thisConnection.CreateCommand();
            thisCommand.CommandText = "select count(*) from customers";

            //ExecuteScalar：执行只返回一个值的SQL命令。
            object countResult = thisCommand.ExecuteScalar();
            Console.WriteLine("Count of Customers={0}",countResult);

            Console.ReadLine();

            thisConnection.Close();
        }
    }
}

结果为：

Count of Customers=91

补充：软件开发 , C# ,