HOW CAN I CHANGE THE CODE IN MY DECODE?

Question

Is it possible to do a DECODE where a number or phrase could be returned
depending upon the condition?
Currently I have this DECODE in my SELECT STATEMENT
select
DECODE(
GREATEST( MONTHS_BETWEEN(n.lcl_er_recv_dt,
ADD_MONTHS(n.ind_er_per_end_dt,3)) , 0
,0,NULL,
DECODE(
LEAST( MONTHS_BETWEEN(n.lcl_er_recv_dt,
ADD_MONTHS(n.ind_er_per_end_dt,3)) , 3
,3, 'OVER 3',
TO_CHAR(ROUND(MONTHS_BETWEEN(n.lcl_er_recv_dt,
ADD_MONTHS(n.ind_er_per_end_dt,3)))
) late
from ncoer n,
all_cmd_view acv
where lcl_er_form_cd = '4'
and n.psc_cd not in ('SC01')
and n.PSC_CD = 'UA72'
and n.lcl_er_recv_dt >= '01-MAR-2007'
and n.lcl_er_recv_dt <= '31-MAR-2007'
and n.lcl_er_recv_dt > ADD_MONTHS(ind_er_per_end_dt,3)
and nvl(N.lcl_omit_from_stats_ind,'N') <> 'Y'
and not exists ( select 1
from ncoer_in_error
where ind_ssn = n.ind_ssn
and ind_er_per_end_dt = n.ind_er_per_end_dt
and lcl_er_recv_dt = n.lcl_er_recv_dt)
and acv.cmd_cd = n.mil_cmd_asgn_cd
and NVL(acv.lcl_code_stat,'N') = 'Y'
I have to use the GREATEST FUNCTION to return a value of null if I get a number
less than 0. I have to use the LEAST FUNCTION to return the value 'OVER 3'
when the calculated value is greater than 3.
Could I change it so if the result of the DECODE equals '0' months the phrase
'90 +DAYs'  is returned
or if the result of the DECODE equals '1' month then a '1' is returned
or if the result of the DECODE equals '2' months then a '2' is returned
or if the result of the DECODE equals '3' months then a '3' is returned
or if the result of the DECODE > '3' then a 'OVER 3' is returned.

Answer 1

It never hurts to try it out.
WITH t AS
SELECT 0 col1 FROM DUAL UNION ALL
SELECT 1 FROM DUAL UNION ALL
SELECT 2 FROM DUAL UNION ALL
SELECT 3 FROM DUAL UNION ALL
SELECT 4 FROM DUAL)
SELECT
  col1                    col1
  ,DECODE(col1
          ,0, '90 +DAYs'
          ,1, '1'
          ,2, '2'
          ,3, '3'
          ,'OVER 3')      test_decode
FROM
  t;
COL1                   TEST_DECODE
0                      90 +DAYs   
1                      1          
2                      2          
3                      3          
4                      OVER 3     
5 rows selected