我怎样才能从一个代码中的两个不同的表中选择？ ？

Question

我使用两次SQLReader的原因我不得不从两个不同的表我怎么能做到这一点有一个代码选择这里是我的代码：

首先SQLReader的：

SqlCommand sqlCmd = new SqlCommand("SELECT Name from Customers where name = '"+textview2.Text+"'", con); 
     SqlDataReader sqlReader = sqlCmd.ExecuteReader(); 

     while (sqlReader.Read()) 
     { 
      textview1.Text = (sqlReader["Name"].ToString()); 


     } 
     sqlReader.Close(); 

二读：

SqlCommand cmd = new SqlCommand("Select Mobile from Informations where Mobile = '"+textview3.Text+"'", con); 
     SqlDataReader sqlReader2 = cmd.ExecuteReader(); 
     while (sqlReader2.Read()) 
     { 
      textview4.Text = (sqlReader2["Mobile"].ToString()); 
     } 

     sqlReader2.Close(); 

我想创建一个代码而不是两个。

Answer 1

首先您需要使用参数化查询。我邀请您搜索为什么这是构建sql查询的强制方式，并尽快删除字符串连接的使用。之后，你可以加入两个命令一起使用SqlDataReader的数据NextResult方法来达到你的第二个数据

// Both commands text are passed to the same SqlCommand 
string cmdText = @"SELECT Name from Customers where name = @name; 
        SELECT Mobile from Informations where Mobile = @mobile"; 
SqlCommand sqlCmd = new SqlCommand(cmdText, con); 

// Set the parameters values.... 
sqlCmd.Parameters.Add("@name", SqlDbType.NVarChar).Value = textview2.Text 
sqlCmd.Parameters.Add("@mobile", SqlDbType.NVarChar).Value = textview3.Text 
SqlDataReader sqlReader = sqlCmd.ExecuteReader(); 
while (sqlReader.HasRows) 
{ 
    // Should be only one record, but to be safe, we need to consume 
    // whatever there is in the first result 
    while(sqlReader.Read()) 
     textview1.Text = (sqlReader["Name"].ToString()); 

    // Move to the second result (if any) 
    if(sqlReader.NextResult()) 
    { 
      // Again, we expect only one record with the mobile searched 
      // but we need to consume all the possible data 
     while(sqlReader.Read()) 
      textview4.Text = (sqlReader["Mobile"].ToString()); 
    } 
} 
sqlReader.Close(); 

顺便说一句，你已经知道了名字和手机，那你为什么执行该代码？