Search value problem in c#

Hello sir,

I have a problem in search values in ms access datebase searching date wise

search a values is date wise ex: 4/1/2012 to 4/30/2012 but it's shows some datavalues are missing i attached the screen short below the word document

but i  searched value is ex: 4/1/2012 to 5/1/2012 it's correctly  view of month wise full data values

Kindly please reffer my word doc with clear screen short

my search button code is

 private void button1_Click(object sender, EventArgs e)
        {
           
           
            double sum1 = 0, sum2 = 0, netbal = 0;
            int j = 0;
            //string str = "select * from purmonth where purchasedate between ('" + textBox2.Text + "')and ('" + textBox3.Text + "') and cusid = ('" + comboBox1 .Text  + "') or paiddate between ('" + textBox4.Text + "') and ('" + textBox5.Text + "') and cusid = ('" + comboBox1 .Text  + "')";
            string str = "select * from SalesMonth where SaleDate between ('" + dateTimePicker1.Text + "')and ('" + dateTimePicker2.Text + "') and SalecustomerID = ('" + comboBox1.Text + "') or PaidDate between ('" + dateTimePicker3.Text + "') and ('" + dateTimePicker4.Text + "') and  SalecustomerID = ('" + comboBox1.Text + "')";
            com = new OleDbCommand(str, con);

            DataSet vds = new DataSet();
            OleDbDataAdapter vda = new OleDbDataAdapter(com);
            vda.Fill(vds, "res");

            dataGridView1.DataSource = vds.Tables["res"];
            for (int i = 0; i < dataGridView1.Rows.Count; ++i)
            {

                sum1 += Convert.ToInt32(dataGridView1.Rows[i].Cells[9].Value);
            }

            for (int i = 0; i < dataGridView1.Rows.Count; ++i)
            {
                sum2 += Convert.ToInt32(dataGridView1.Rows[i].Cells[8].Value);
            }


            j = dataGridView1.Rows.Count - 1;
            dataGridView1.Rows[j].Cells[9].Value = sum1.ToString("n");
            dataGridView1.Rows[j].Cells[8].Value = sum2.ToString("n");
            netbal = sum1 - sum2;
            dataGridView1.Rows[j].Cells[10].Value = netbal.ToString("n");
            dataGridView1.Rows[j].Cells[5].Value = "TOTAL";
            vda.Dispose();
            com.Dispose();

i have attached the code with screen short

kindly help me

thinking you