How to get row number from selected rows in Oracle

There is no inherent ordering to a table. So, the row number itself is a meaningless metric.

However, you can get the row number of a result set by using the ROWNUM psuedocolumn or the ROW_NUMBER() analytic function, which is more powerful.

As there is no ordering to a table both require an explicit ORDER BY clause in order to work.

select rownum, a.*  from ( select *           from student          where name like '%ram%'          order by branch                ) a

or using the analytic query

select row_number() over ( order by branch ) as rnum, a.*  from student where name like '%ram%'

Your syntax where name is like ... is incorrect, there's no need for the IS, so I've removed it.

The ORDER BY here relies on a binary sort, so if a branch starts with anything other than B the results may be different, for instance b is greater than B.

you can just do

select rownum, l.* from student  l where name like %ram%

this assigns the row number as the rows are fetched (so no guaranteed ordering of course).

if you wanted to order first do:

select rownum, l.*  from (select * from student l where name like %ram% order by...) l;

I think using

select rownum st.Branch   from student st  where st.name like '%ram%'

is a simple way; you should add single quotes in the LIKE statement. If you use row_number(), you should add over (order by 'sort column' 'asc/desc'), for instance:

select st.branch, row_number() over (order by 'sort column' 'asc/desc')    from student st  where st.name like '%ram%'