String union_friends =
            "CREATE VIEW UNIONED_FRONDS AS " +
            "SELECT F1.USER1_ID AS UNIONFRIEND1, F1.USER2_ID AS UNIONFRIEND2 " +
            "FROM " + FriendsTable + " F1 " +
            "UNION " +
            "SELECT F2.USER2_ID, F2.USER1_ID " +
            "FROM " + FriendsTable + " F2 ";


            String mutual_friends =
            "CREATE VIEW MUTUAL_FRONDS AS " +
            "SELECT UF1.UNIONFRIEND1 AS FRIEND1, UF2.UNIONFRIEND1 AS MUTUALFRIEND, UF2.UNIONFRIEND2 AS FRIEND2 " +
            "FROM UNIONED_FRONDS UF1, UNIONED_FRONDS UF2 " +
                "WHERE UF1.UNIONFRIEND2 = UF2.UNIONFRIEND1 " +
                "AND UF1.UNIONFRIEND1 < UF2.UNIONFRIEND2 " +
                "AND NOT EXISTS ( " +
                    "SELECT F1.USER1_ID,  F1.USER2_ID " +
                    "FROM " + FriendsTable + " F1 " +
                        "WHERE UF1.UNIONFRIEND1 = F1.USER1_ID " +
                        "AND UF2.UNIONFRIEND2 = F1.USER2_ID " +
                ")";


            String order_mutual_friends =
            "CREATE VIEW ORDERED_MUTUAL_FRONDS AS " +
            "SELECT * " +
            "FROM ( " +
                "SELECT FMF.FRIEND1 AS FRIEND1, FMF.FRIEND2 AS FRIEND2 " +
                "FROM MUTUAL_FRONDS FMF " +
                    "GROUP BY FMF.FRIEND1, FMF.FRIEND2 " +
                    "ORDER BY COUNT(FMF.MUTUALFRIEND) DESC, FMF.FRIEND1 ASC, FMF.FRIEND2 ASC " +
                ")" + " " +
                "WHERE ROWNUM <= " + num;

            //query string
            String top_user_pair =
            "SELECT U1.USER_ID, U1.FIRST_NAME, U1.LAST_NAME,  U2.USER_ID, U2.FIRST_NAME, U2.LAST_NAME " +
            "FROM " + UsersTable + " U1, " + UsersTable + " U2, MUTUAL_FRONDS FMF " +
                "WHERE U1.USER_ID < U2.USER_ID " +
                "AND FMF.FRIEND1 = U1.USER_ID " +
                "AND FMF.FRIEND2 = U2.USER_ID " +
                "AND (U1.USER_ID, U2.USER_ID) IN ( " +
                    "SELECT * " +
                    "FROM  ORDERED_MUTUAL_FRONDS " +
                ")" + " " +
                "GROUP BY U1.USER_ID, U1.FIRST_NAME, U1.LAST_NAME,  U2.USER_ID, U2.FIRST_NAME, U2.LAST_NAME " +
                "ORDER BY COUNT(FMF.MUTUALFRIEND) DESC, U1.USER_ID ASC, U2.USER_ID ASC";

            String top_mutual =
            "SELECT FMF.FRIEND1, FMF.FRIEND2, U3.USER_ID, U3.FIRST_NAME, U3.LAST_NAME " +
            "FROM " + UsersTable + " U3, MUTUAL_FRONDS FMF, MUTUAL_FRONDS MF " +
                "WHERE MF.MUTUALFRIEND = U3.USER_ID " +
                "AND MF.FRIEND1 = FMF.FRIEND1 " +
                "AND MF.FRIEND2 = FMF.FRIEND2 " +
                "AND (FMF.FRIEND1, FMF.FRIEND2) IN ( " +
                    "SELECT * " +
                    "FROM ORDERED_MUTUAL_FRONDS " +
                ")" + " " +
                "GROUP BY FMF.FRIEND1, FMF.FRIEND2, U3.USER_ID, U3.FIRST_NAME, U3.LAST_NAME " +
                "ORDER BY COUNT(FMF.MUTUALFRIEND) DESC, FMF.FRIEND1 ASC, FMF.FRIEND2 ASC, U3.USER_ID ASC";

            stmt.executeQuery(union_friends);
            stmt.executeQuery(mutual_friends);
            stmt.executeQuery(order_mutual_friends);

            Statement stmt0 = oracle.createStatement(FakebookOracleConstants.AllScroll, FakebookOracleConstants.ReadOnly);

            ResultSet user_pair_info = stmt0.executeQuery(top_user_pair);
            ResultSet shared_mutual = stmt.executeQuery(top_mutual);

            while(user_pair_info.next()) {
                UserInfo u1 = new UserInfo(user_pair_info.getLong(1), user_pair_info.getString(2), user_pair_info.getString(3));
                UserInfo u2 = new UserInfo(user_pair_info.getLong(4), user_pair_info.getString(5), user_pair_info.getString(6));
                UsersPair up = new UsersPair(u1, u2);

                while (shared_mutual.next() && shared_mutual.getLong(1) == user_pair_info.getLong(1) && shared_mutual.getLong(2) == user_pair_info.getLong(4) ){
                    UserInfo u3 = new UserInfo(shared_mutual.getLong(3), shared_mutual.getString(4), shared_mutual.getString(5));
                    up.addSharedFriend(u3);
                }

                shared_mutual.previous();

                results.add(up);
            }

            stmt.executeQuery("DROP VIEW UNIONED_FRONDS CASCADE CONSTRAINTS");
            stmt.executeQuery("DROP VIEW MUTUAL_FRONDS CASCADE CONSTRAINTS");
            stmt.executeQuery("DROP VIEW ORDERED_MUTUAL_FRONDS CASCADE CONSTRAINTS");

            shared_mutual.close();
            user_pair_info.close();
            stmt0.close();
            stmt.close();