Create Function-Based Index example
-- create Index Function-Based CREATE INDEX CITY_IDX ON STUDENTS (UPPER(CITY)); CREATE INDEX PRICE_IDX ON COURSE(PRICE - DISCOUNT);
Output:
index CITY_IDX created. 
index PRICE_IDX created.
Check indexes
select INDEX_NAME, INDEX_TYPE, FUNCIDX_STATUS
from USER_INDEXES
WHERE INDEX_NAME IN 
  (SELECT OBJECT_NAME FROM 
    (SELECT * 
    FROM USER_OBJECTS 
    WHERE OBJECT_TYPE='INDEX' 
    ORDER BY CREATED DESC) 
  WHERE ROWNUM < =2);
Output:
| INDEX_NAME | INDEX_TYPE | FUNCIDX_STATUS | 
|---|---|---|
| PRICE_IDX | FUNCTION-BASED NORMAL | ENABLED | 
| CITY_IDX | FUNCTION-BASED NORMAL | ENABLED |