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）。

 1 using System;

 2 using System.Collections.Generic;

 3 using System.Text;

 4 

 5 using System.Data;

 6 using System.Data.SqlClient;

 7 using System.Data.Common;

 8 

 9 namespace AutoLotDataReader

10 {

11     class Program

12     {

13         static void Main(string[] args)

14         {

15             Console.WriteLine("***** Fun with Data Readers *****\n");

16 

17             #region Connection string builder logic

18             // Create a connection string via the builder object.

19             // SqlConnectionStringBuilder，这样就不用写连接字符串了

20             SqlConnectionStringBuilder cnStrBuilder =

21               new SqlConnectionStringBuilder();

22             //cnStrBuilder.InitialCatalog = "AutoLot";

23             //cnStrBuilder.DataSource = @"(local)\SQLEXPRESS"; 

24             cnStrBuilder.InitialCatalog="Northwind";

25             cnStrBuilder.DataSource = @"NLH774";

26             cnStrBuilder.ConnectTimeout = 30;

27             cnStrBuilder.IntegratedSecurity = true;

28 

29             SqlConnection cn = new SqlConnection();

30             cn.ConnectionString = cnStrBuilder.ConnectionString;

31             cn.Open();

32             ShowConnectionStatus(cn);

33             #endregion

34 

35             // Create a SQL command object w/ 2 select statements.

36             //执行两句SQL语句

37             //string strSQL = "Select * From Inventory;Select * from Customers";

38             string strSQL = "Select * From Employees;Select * from Customers";

39             SqlCommand myCommand = new SqlCommand(strSQL, cn);

40 

41             // Obtain a data reader a la ExecuteReader().

42             SqlDataReader myDataReader;

43             myDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection);

44 

45             #region Loop over each table.

46             do

47             {

48                 //遍历一个查询中的记录

49                 while (myDataReader.Read())

50                 {

51                     //遍历按行输出一个记录的信息，格式列名=列值

52                     Console.WriteLine("***** Record *****");    

53                     for (int i = 0; i < myDataReader.FieldCount; i++)

54                     {

55                         Console.WriteLine("{0} = {1}",

56                           myDataReader.GetName(i),

57                           myDataReader.GetValue(i).ToString().Trim());

58                     }

59                     Console.WriteLine();

60                 }

61 

62                 Console.WriteLine("**********************************");

63             } while (myDataReader.NextResult());    //执行下一个结果集查询（Select * from Customers）

64             #endregion

65 

66             // Because we specified CommandBehavior.CloseConnection, we 

67             // don't need to explicitly call Close() on the connection.

68             myDataReader.Close();

69             Console.ReadLine();

70         }

71 

72         #region Helper method

73         static void ShowConnectionStatus(DbConnection cn)

74         {

75             // Show various stats about current connection object.

76             Console.WriteLine("***** Info about your connection *****");

77             Console.WriteLine("Database location: {0}", cn.DataSource);

78             Console.WriteLine("Database name: {0}", cn.Database);

79             Console.WriteLine("Timeout: {0}", cn.ConnectionTimeout);

80             Console.WriteLine("Connection state: {0}\n", cn.State.ToString());

81         }

82         #endregion

83     }

84 }

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。