Get data starting from the middle of the table - sql

Question

I have a question. I want to get data from the middle of the table. But the problem is I can't start from the middle. I have read that rownum can't be used for this. But i dont know how to do this with another method. Anyone have any clue how to do this? Thank you.
Below is an example.
select count(1) --9857
from time_day_dm
where rownum between 5000 and 9857
The output would be 0.
What i expect would be 4857.

Answer 1

rownum won't help here (as you already know).
What you might do, is to use a couple of analytic functions (count, to find number of rows in the table; row_number, to sort them).
Here's an example based on Scott's emp table. This is its contents:
SQL> select empno, ename, job, sal
2 from emp
3 order by ename;
EMPNO ENAME JOB SAL
---------- ---------- --------- ----------
7876 ADAMS CLERK 1100
7499 ALLEN SALESMAN 1600
7698 BLAKE MANAGER 2850
7782 CLARK MANAGER 2450
7902 FORD ANALYST 3000
7900 JAMES CLERK 950
7566 JONES MANAGER 2975
7839 KING PRESIDENT 5000
7654 MARTIN SALESMAN 1250
7934 MILLER CLERK 1300
7788 SCOTT ANALYST 3000
7369 SMITH CLERK 800
7844 TURNER SALESMAN 1500
7521 WARD SALESMAN 1250
14 rows selected.
Query you might be interested in looks like this:
SQL> with temp as
2 (select empno, ename, job, sal,
3 row_number() over (order by ename) rn,
4 count(*) over () cnt
5 from emp
6 )
7 select *
8 from temp
9 where rn between cnt/2 and cnt;
EMPNO ENAME JOB SAL RN CNT
---------- ---------- --------- ---------- ---------- ----------
7566 JONES MANAGER 2975 7 14
7839 KING PRESIDENT 5000 8 14
7654 MARTIN SALESMAN 1250 9 14
7934 MILLER CLERK 1300 10 14
7788 SCOTT ANALYST 3000 11 14
7369 SMITH CLERK 800 12 14
7844 TURNER SALESMAN 1500 13 14
7521 WARD SALESMAN 1250 14 14
8 rows selected.
SQL>