Question

Can we use nested analytic function within analytic function? We can use another analytic function within expression or not?

Please provide me one example.

Answer 1

No, you cannot nest analytic functions. From the manual:

You cannot nest analytic functions by specifying any analytic function
in any part of the analytic_clause. However, you can specify an
analytic function in a subquery and compute another analytic function
over it.

For example:

SQL> select sum(count(*) over ()) over () from dual;
select sum(count(*) over ()) over () from dual
           *
ERROR at line 1:
ORA-30483: window  functions are not allowed here