using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace QueryTablesByLinq
{
public partial class Frm_Main : Form
{
public Frm_Main()
{
InitializeComponent();
}
void Frm_Main_Load Private (SENDER Object, EventArgs E)
{
String the ConnectionString = "Server-GI7E47AND9R WIN = \ the LS; Database = db_TomeTwo; UID = SA; pwd ="; // declare the connection string
using (SqlConnection Conn = new SqlConnection ( ConnectionString )) // create a database connection object
{
String sqlstr = "SELECT from tb_Register"; // definition of query
SqlDataAdapter da = new SqlDataAdapter (sqlstr, Conn); // Create a data object bridge
DataSet ds = new DataSet (); / / create data objects
da.Fill (ds, "register") ; // fill first data table data to the DataSet
sqlstr = "the SELECT from tb_Sale"; // define the query
da.SelectCommand.CommandText = sqlstr; // specified The second query
da.Fill (ds, "sale") ; // fill the second data table data to the DataSet
// query pharmaceutical sales record information
var = Result from R & lt ds.Tables in [ "Register"] AsEnumerable ().
the Join ds.Tables in S [ "Sale"]. AsEnumerable ()
ON r.Field <String> ( "No Drug") equals s.Field <string> ( " No Drug")
SELECT new new
{
drug_name R & lt = [ "Drug name "] .ToString (),
drug_factory R & lt = [" manufacturer "] .ToString (),
drug_sale S = [" sales "] .ToString ()
};
foreach (var item in result) // traverse the output results
{
RichTextBox1.Text + = "Drug Name:" + item.drug_name + " ** manufacturer:" + item.drug_factory + " ** Sales:" + item.drug_sale + "\ n-";
}
}
}
}
}