" Incorrect syntax near ')' " i need help please, what is the wrong with this code

private void linkLabel1_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
        {
            string cs = @"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\SATDB.mdf;Integrated Security=True;User Instance=True";
            using (SqlConnection con = new SqlConnection(cs))
            {
                con.Open();
                SqlTransaction txn = con.BeginTransaction();
                string sql = "GET_FILESTREAM_TRANSACTION_CONTEXT(), SELECT Trial_Addmission.PathName() from Sat";
                SqlCommand cmd = new SqlCommand(sql, con, txn);
                SqlDataReader rdr = cmd.ExecuteReader();
                while (rdr.Read())
                {
                    string filePath = rdr[0].ToString();
                    byte[] objContext = (byte[])rdr[1];
                    string Name = rdr[2].ToString();

                    SqlFileStream sfs = new SqlFileStream(filePath, objContext, FileAccess.Read);

                    byte[] buffer = new byte[(int)sfs.Length];
                    sfs.Read(buffer, 0, buffer.Length);
                    sfs.Close();
                }

                rdr.Close();
                txn.Commit();
                con.Close();
            }
        }