scott@ORCL> CREATE INDEX SCOTT.i_dept_name
  2   ON SCOTT.DEPT(DNAME)
  3  ;

Index created.

scott@ORCL> Analyze Table SCOTT.DEPT Compute Statistics ;

Table analyzed.

scott@ORCL> select * from scott.dept where
  2  rowid in (
  3  select /*+ index_ffs(a i_dept_dname) */
  4  rowid from scott.dept a where dname like '%A%')
  5  ;