调试易

数据库里的汇总日期是2008-07-20,但是输出之后在textBox19.Text显示的却是2008-07-20 00:00:00,请问怎么让它不显示后面的时分秒???
        private void comboBodw_TextChanged(object sender, EventArgs e)
        {
            string sql1 = "select * from danweihuizong where 汇总日期='" + dateTimePicker1.Value.ToString("yyyy-MM-dd") + "'and 单位='" + comboBodw.Text + "'";
            SqlCommand cmd1 = new SqlCommand(sql1, conn);
            conn.Open();
            SqlDataReader dr1 = cmd1.ExecuteReader();
            while (dr1.Read())
            {
                textBox19.Text = dr1["汇总日期"].ToString();
            }
            dr1.Close();
            conn.Close();
        }