Display rows as page wise

Question

Hello,
I have a requirement to display the limited records from the query which returns large number of records.
Assume that select * from orders order by order_id is giving me 1000 rows.
now i have to do a filter, display records from 25 to 50 or 50 to 150 etc...
i can pass the start range and number of records to be displayed as an input parameter to the query.
above example, start range is 25 and number of records should display is 25 from 25th record to next 25 records. (something like , select * from orders order by order id where rownum between 25 and 50)
again, start range is 50 and number of next records should display is 100 starting from 50th record to next 150 record.(something like , select * from orders order by order id where rownum between 50 and 150)
how can i achive this using a query. remember the start range and number of display count i can pass as an input to the query.
Appreciating the great help...
good day

Answer 1

Are you really sure that you need PARTITION BY clause in the row_number() function?
SQL> var p_start number
SQL> var p_range number
SQL> exec :p_start := 2
PL/SQL procedure successfully completed.
SQL> exec :p_range := 6
PL/SQL procedure successfully completed.
SQL> SELECT *
  2    FROM (SELECT   a.*, rownum rn
  3              FROM emp a
  4          ORDER BY sal)
  5   WHERE rn BETWEEN :p_start AND :p_start + :p_range
  6  /
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO         RN
      7900 JAMES      CLERK           7698 03-DEC-81        950          1         30          8
      7654 MARTIN     SALESMAN        7698 28-SEP-81       1250          1         30          5
      7844 TURNER     SALESMAN        7698 08-SEP-81       1500          1         30          7
      7499 ALLEN      SALESMAN        7698 20-FEB-81       1600          1         30          6
      7782 CLARK      MANAGER         7839 09-JUN-81       2450          1         10          3
      7698 BLAKE      MANAGER         7839 01-MAY-81       2850          1         30          2
      7566 JONES      MANAGER         7839 02-APR-81       2975          1         20          4
7 rows selected.
SQL> SELECT *
  2     FROM (SELECT   a.*, row_number() over (order by sal) rn
  3               FROM emp a
  4           ORDER BY sal)
  5   WHERE rn BETWEEN :p_start AND :p_start + :p_range
  6  /
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO         RN
      7900 JAMES      CLERK           7698 03-DEC-81        950          1         30          2
      7876 ADAMS      CLERK           7788 12-JAN-83       1100          1         20          3
      7521 WARD       SALESMAN        7698 22-FEB-81       1250          1         30          4
      7654 MARTIN     SALESMAN        7698 28-SEP-81       1250          1         30          5
      7934 MILLER     CLERK           7782 23-JAN-82       1300          1         10          6
      9999 MILLER     CLERK           7782 23-JAN-82       1300          1         10          7
      7844 TURNER     SALESMAN        7698 08-SEP-81       1500          1         30          8
7 rows selected.
SQL>
SQL>Cheers
Sarma.