string strSQL = "Select * From Employees;Select * from Customers";执行两次查询

SqlCommand对象的字符串SQL命令可以做多个，
以查询为例，用到SqlDataReader的一些方法，如ExecuteReader(),Read()(一条命令内的移动至下一记录)，NextResult()（移动到下一个命令并执行）。

  using System;
  using System.Collections.Generic;
  using System.Text;

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

  namespace AutoLotDataReader
 {
     class Program
     {
         static void Main(string[] args)
         {
             Console.WriteLine("***** Fun with Data Readers *****\n");

             #region Connection string builder logic
             // Create a connection string via the builder object.
             // SqlConnectionStringBuilder，这样就不用写连接字符串了
             SqlConnectionStringBuilder cnStrBuilder =
               new SqlConnectionStringBuilder();
             //cnStrBuilder.InitialCatalog = "AutoLot";
             //cnStrBuilder.DataSource = @"(local)\SQLEXPRESS";
             cnStrBuilder.InitialCatalog="Northwind";
             cnStrBuilder.DataSource = @"NLH774";
             cnStrBuilder.ConnectTimeout = ;
             cnStrBuilder.IntegratedSecurity = true;

             SqlConnection cn = new SqlConnection();
             cn.ConnectionString = cnStrBuilder.ConnectionString;
             cn.Open();
             ShowConnectionStatus(cn);
             #endregion

             // Create a SQL command object w/ 2 select statements.
             //执行两句SQL语句
             //string strSQL = "Select * From Inventory;Select * from Customers";
             string strSQL = "Select * From Employees;Select * from Customers";
             SqlCommand myCommand = new SqlCommand(strSQL, cn);

             // Obtain a data reader a la ExecuteReader().
             SqlDataReader myDataReader;
             myDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection);

             #region Loop over each table.
             do
             {
                 //遍历一个查询中的记录
                 while (myDataReader.Read())
                 {
                     //遍历按行输出一个记录的信息，格式列名=列值
                     Console.WriteLine("***** Record *****");
                     for (int i = ; i < myDataReader.FieldCount; i++)
                     {
                         Console.WriteLine("{0} = {1}",
                           myDataReader.GetName(i),
                           myDataReader.GetValue(i).ToString().Trim());
                     }
                     Console.WriteLine();
                 }

                 Console.WriteLine("**********************************");
             } while (myDataReader.NextResult());    //执行下一个结果集查询（Select * from Customers）
             #endregion

             // Because we specified CommandBehavior.CloseConnection, we
             // don't need to explicitly call Close() on the connection.
             myDataReader.Close();
             Console.ReadLine();
         }

         #region Helper method
         static void ShowConnectionStatus(DbConnection cn)
         {
             // Show various stats about current connection object.
             Console.WriteLine("***** Info about your connection *****");
             Console.WriteLine("Database location: {0}", cn.DataSource);
             Console.WriteLine("Database name: {0}", cn.Database);
             Console.WriteLine("Timeout: {0}", cn.ConnectionTimeout);
             Console.WriteLine("Connection state: {0}\n", cn.State.ToString());
         }
         #endregion
     }
 }

虽然可以这样，但我觉得从软件编码规范、清晰可读性上说，最好还是不要这么操作。

最好应该分开执行不同的命令，大不了多声明几个字符串命令而已。