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();
}
private void Frm_Main_Load(object sender, EventArgs e)
{
string ConnectionString = "server=WIN-GI7E47AND9RLS; database=db_TomeTwo; uid=sa; pwd=";//声明衔接字符串
using (SqlConnection Conn = new SqlConnection(ConnectionString))//创立数据库衔接目标
{
string sqlstr = "select * from tb_Register";//界说查询句子
SqlDataAdapter da = new SqlDataAdapter(sqlstr, Conn);//创立数据桥接器目标
DataSet ds = new DataSet();//创立数据目标
da.Fill(ds, "register");//填充第一个数据表数据到DataSet
sqlstr = "select * from tb_Sale";//界说查询句子
da.SelectCommand.CommandText = sqlstr;//指定第二条查询句子
da.Fill(ds, "sale");//填充第二个数据表数据到DataSet
//查询有出售记载的药品信息
var result = from r in ds.Tables["register"].AsEnumerable()
join s in ds.Tables["sale"].AsEnumerable()
on r.Field("药品编号") equals s.Field("药品编号")
select new
{
drug_name = r["药品称号"].ToString(),
drug_factory = r["生产厂家"].ToString(),
drug_sale = s["出售额"].ToString()
};
foreach (var item in result) //遍历输出查询成果
{
richTextBox1.Text += "药品称号：" + item.drug_name + "******生产厂家：" + item.drug_factory + "******出售额：" + item.drug_sale + "
";
}
}
}
}
}
