Basically before i asked a question on how to return the null values from a columns found from a table in sql. Now i need to know how to do the same thing but for two columns and putting the user name near them which is caught from another column. This means i have 3 tables.
基本上在我问一个关于如何从sql中的表中找到的列返回空值的问题之前。现在我需要知道如何做同样的事情,但是对于两列并将用户名放在它们附近,这是从另一列捕获的。这意味着我有3张桌子。
using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace sql_connection
{
class Program
{
static void Main(string[]args)
{
string conn=null;
SqlConnection connection;
conn=("Data Source=Database\\SQL2012;Initial Catalog=Table;User ID=user;Password=example");
connection=new SqlConnection(conn);
try{
connection.Open();
Console.Writeline("Connection Open!");
SqlCommand cmd= new SqlCommand("SELECT tablein,tableout,tableuser FROM [dbo].[tb_Showingnull]"WHERE tablein AND tableout IS NULL);
cmd.Connection = connection;
SqlDataReader reader = cmd.ExecuteReader();
while(reader.Read())
{
Console.WriteLine("{2}, {1} , {0}", reader["tablein"] == DBNull.Value? "NULL" : reader["tablein"].ToString(); reader["tableout"] == DBNull.Value? "NULL" : reader["tableout"].ToString(); reader["tableuser"].ToString();
}
connection.Close();
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
}
}
}
}
1 个解决方案
#1
instead of
SqlCommand cmd=
new SqlCommand("SELECT tablein,tableout,tableuser FROM
[dbo].[tb_Showingnull]"WHERE tablein AND tableout IS NULL);
Use
SqlCommand cmd=
new SqlCommand("SELECT tablein,tableout,tableuser FROM
[dbo].[tb_Showingnull] WHERE tablein IS NULL AND tableout IS NULL");
#1
instead of
SqlCommand cmd=
new SqlCommand("SELECT tablein,tableout,tableuser FROM
[dbo].[tb_Showingnull]"WHERE tablein AND tableout IS NULL);
Use
SqlCommand cmd=
new SqlCommand("SELECT tablein,tableout,tableuser FROM
[dbo].[tb_Showingnull] WHERE tablein IS NULL AND tableout IS NULL");