Write a Query to reverse the string without reverse function

Input:

ORACLE

Output:

ELCARO

STEP 1:

with t as (select 'ORACLE' d from dual)

 select d from t connect by level <=length(d);

Output:

ORACLE
ORACLE
ORACLE
ORACLE
ORACLE
ORACLE

STEP 2: 

with t as (select 'ORACLE' d from dual)

select d,substr(d,level,1) from t connect by level <=length(d);

 Output:

ORACLE    O
ORACLE    R
ORACLE    A
ORACLE    C
ORACLE    L
ORACLE    E

STEP 3:

with t as (select 'ORACLE' d from dual)

select d,substr(d,level,1),level from t connect by level <=length(d);

 Output:

ORACLE    O    1
ORACLE    R    2
ORACLE    A    3
ORACLE    C    4
ORACLE    L    5
ORACLE    E    6

STEP 4:

with t as (select 'ORACLE' d from dual)

select listagg(s) within group (order by l) col from

(select d,substr(d,level,1) s,level l from t connect by level <=length(d));

 Output:

    ORACLE 

 

STEP 5:

with t as (select 'ORACLE' d from dual)

select listagg(s) within group (order by l desc) col from

(select d,substr(d,level,1) s,level l from t connect by level <=length(d));

Output:

   ELCARO