OleDbConnection con = new OleDbConnection("Provider User ID= stud; Password= stud");

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            con.Open();
            OleDbDataAdapter zap = new OleDbDataAdapter(" Select name_long From o_use_base_units WHERE (TO_CHAR(from_date,'YY')) = '16' AND (TO_CHAR(to_date,'YY')) = '50'" , con);
            DataTable dt = new DataTable();
            zap.Fill(dt);
            dataGridView1.DataSource = dt;
            con.Close();
        }