Gridview duplicate values..

public partial class InstSentIntForFran : System.Web.UI.Page
{
    SqlConnection cn;
    autheticate at = new autheticate();
    protected void Page_Load(object sender, EventArgs e)
    {
        
        getCandidateSentIntrest();
    }
    public void getCandidateSentIntrest()
    {
        try
        {
            cn = at.sqlcon();
            //SqlDataAdapter sda = new SqlDataAdapter(strqry, cn);
            //DataSet ds = new DataSet();

            string strqry = getQuery();
 
            SqlDataAdapter sda = new SqlDataAdapter(strqry, cn);
            DataSet ds = new DataSet();
            ds.Clear();
            sda.Fill(ds);
            int dd = ds.Tables[0].Rows.Count;
            GridView1.DataSource = ds;
            GridView1.DataBind();
          
          
        }
        catch (Exception err)
        {
            lblres.Text = err.Message;
        }
    }


    string getQuery()
    {

         string sentintrestType = "";
        if (Request.QueryString["sentintrestType"] != null)
        {
            sentintrestType = Request.QueryString["sentintrestType"].ToString();
        }
        string qry = "Select C.Franchise_Brand_Name,p.Franchise_Offer_Industry,p.Franchise_Offer_ExpnReg,p.Franchise_OfferInvReqMin,p.Franchise_Offer_InvReqMx,p.Franchise_Offer_MinSqft,p.Franchise_Offer_MaxSqFt,I.Int_Date from User_Details U,Franchise_Details C,Franchise_Offer_Details p,Intrests I where I.Applicants_User_Name='" + Session["uid"] + "' and I.Receivers_User_Name = U.User_Name and I.Receivers_User_Name = C.User_Name and p.User_Name = C.User_Name  ";
        
       
        if (sentintrestType == "Brand_Int_Frn")
        {
            qry = qry + "and I.Brand_Int_Frn='true'";
        }
        qry = qry + "ORDER BY I.Int_Date DESC";
        return qry;

    }

}