What is wrong with my codes?

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C#

C#4.0

I want to extract admission_no from users but I don't want the phone_no and merge with admission_no with all the data from test. After that I want to insert them into one table which is the merge table.
Example Tables
users
admission_no,phone_no
testo
subject_id,subject_name,admission_no,date,time,venue,seat_no
merge
subject_id,subject_name,admission_no,date,time,venue,seat_no
HOW AM I SUPPOSE TO DO THAT IN C#?PLEASE HELP.ITS REALLY URGENT.
BELOW IS MY CURRENT CODES..

protected void Button1_Click(object sender, EventArgs e)
   {
     SqlConnection conn = new SqlConnection("Data Source= EN12-2-20-PC01\\SQLEXPRESS;" + "Initial Catalog=ssms;Integrated Security=SSPI");
     SqlDataAdapter adapSel;

     conn.Open();
     foreach (GridViewRow gvr in GridView2.Rows)   //loop through GridView
     {
       string viewqry = "INSERT INTO merge(subject_id,subject_name,admission_no,date,time,venue,seat_no) " + "(SELECT U.admission_no,T.subject_name,T.date,T.time,T.venue,T.seat_no " + "From users As U INNER JOIN testo As T ON U.admission_no = T.admission_no) VALUES ('" + gvr.Cells[0].Text + "','" + gvr.Cells[1].Text + "','" + gvr.Cells[2].Text + "','" + gvr.Cells[3].Text + "','" + gvr.Cells[4].Text + "','" + gvr.Cells[5].Text + "','" + gvr.Cells[6].Text + "')";
       adapSel = new SqlDataAdapter(viewqry, conn);

       DataSet dsSel = new DataSet();
       adapSel.Fill(dsSel);
       GridView2.DataSource = dsSel;
       GridView2.DataBind();
       conn.Close();

    }