string querySQL = "";//this is where you pass in you query sting
//just an example connections string
           string connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="access.mdb";
//create and open our connections
OleDbConnection database database = new OleDbConnection(connectionString);
                database.Open();
 
//create a command, and datatable, and adapter
            OleDbCommand SQLQuery = new OleDbCommand();
            DataTable data = null;
            SQLQuery.Connection = null;
            OleDbDataAdapter dataAdapter = null;
            //---------------------------------
            SQLQuery.CommandText = querySQL;
            SQLQuery.Connection = database;
            data = new DataTable();
            dataAdapter = new OleDbDataAdapter(SQLQuery);
            dataAdapter.Fill(data);
           //you now have a full data table
           // now just loop through the data and add the rows to
           //the list box this just looks through the table for each row,
          //and if the row has an entry in the column "aColumn"
           //they are added to the list box.
            for (int i = 0; i < data.Rows.Count; i++)
             {
 
            string data1 = data.Rows[i]["aColumn"].ToString();
            listView1.Items.Add(data1);
             }
 

 private void button1_Click_1(object sender, EventArgs e)
        {
            if (listBox1.SelectedItems.Count == 0)
            {
                MessageBox.Show("select items");
                return;
            }
            string s = "";
            for (int i = 0; i < listBox1.SelectedItems.Count; i++)
            {
                  if(i==listBox1.SelectedItems.Count-1)
                      s = s + " item='" + listBox1.SelectedItems[i].ToString() + "'";
                  else
                    s=s + " item='" + listBox1.SelectedItems[i].ToString() + "'  or ";
 
            }
            s = "select * from table where " + s;
            MessageBox.Show(s);
        }

string querystr = "SELECT DISTINCT sinif FROM FileTemp WHERE okuladi IN(";
 
                for (int i = 0; i < schoolListBox.SelectedItems.Count; i++)
                {
                    querystr = querystr + "'" + schoolListBox.SelectedItems[i] + "'";
 
                    if (i != schoolListBox.SelectedItems.Count - 1)
                        querystr = querystr + ",";
                    else
                        querystr = querystr + ")";                                        
                }

      SqlDataAdapater adp=new SqlDataAdapter(querystr,"set connection string");
     DataTable dt=new DataTable();
    adp.Fill(dt);
     anotherList.DataSource=dt;
     anotherList.DisplayMember=dt.Columns[0].ColumnName;