Using order by and rownum in massive tables

Question

Hi,
I need to retreive paginated and ordered data from a big table.
I know some different tips using rownum or the RANK() function and subqueries, these tips work well for small amount of data, but I need to get the data from a table with 200.000 entries (not under my control), and with all those methods is necessary to order first the data and then select your range, so performance is extremely poor.
Anybody knows a better solution? it doesn't matter if is plain SQL(better) or PL/SQL.
Thanks in advance

Answer 1

but I was looking for something like the LIMIT in MySQL or TOP in msSQL where all the sorting is made internally and it's really fast If the data needs sorting, I do not think Oracle would take any longer to do that than the others mentioned, unless the other DBs mentioned, only sort the rows that are actually being returned.
As for the LIMIT clause, Oracle already has that clause available when FETCHing from a CURSOR:
SQL> DECLARE
  2      CURSOR emp_cur IS
  3          SELECT * FROM scott.emp;
  4      TYPE emp_rec_table IS TABLE OF emp_cur%ROWTYPE INDEX BY BINARY_INTEGER;
  5      emp_tbl emp_rec_table;
  6  BEGIN
  7      OPEN emp_cur;
  8      LOOP
  9          emp_tbl.DELETE;
10          FETCH emp_cur BULK COLLECT
11              INTO emp_tbl LIMIT 5;
12          EXIT WHEN emp_tbl.COUNT <= 0;
13          dbms_output.put_line(emp_tbl.COUNT || ' rows fetched using LIMIT clause.');
14      END LOOP;
15      CLOSE emp_cur;
16  END;
17  /
5 rows fetched using LIMIT clause.
5 rows fetched using LIMIT clause.
4 rows fetched using LIMIT clause.
PL/SQL procedure successfully completed.
SQL> disconnect
Disconnected from Oracle9i Enterprise Edition Release 9.2.0.3.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.3.0 - Production
SQL>