Case when then not working

Question

In my database, two variable ID and time (varchar2) are there. I want to populate another variable using case when then by putting below conditon to convert like this
But its not working. Can anyone help me
if time =1 day then '1 Day'
time > 2 days and time <=7 days then '2 to 7 days'
time > 8 days and time <=15 days then '8 to 15 days'
else 'not matching'
ID Time
12 1 days
23 244 days
12 2 days
14 4 days
15 6 days
17 9 days
select time,
case WHEN
UPPER(Time) = '1 DAY'
THEN
'1 day'
WHEN
UPPER(Time) Between '2 DAYS' and '7 DAYS'
THEN
'2 to 7 days'
WHEN
UPPER(Time) Between '8 DAYS' and '15 DAYS'
THEN
'8 to 15 days'
ELSE
'Not matching'
END "update time"
from table1

Answer 1

900487 wrote:
In my database, two variable ID and time (varchar2) are there. If you are storing Days in a column store it as NUMBER or INTERVAL data type. The way you have stored the value looks incorrect.
What you can do is extract the number portion of your time column and apply the CASE statement. Something like this
SQL> with t
  2  as
  3  (
  4  select 12 id, '1 days' time1 from dual union all
  5  select 23 id, '244 days' time1 from dual union all
  6  select 12 id, '2 days' time1 from dual union all
  7  select 14 id, '4 days' time1 from dual union all
  8  select 15 id, '6 days' time1 from dual union all
  9  select 17 id, '9 days' time1 from dual
10  )
11   select id,
12          time1,
13          case when time1 = 1              then '1 day'
14               when time1 between 2 and 7  then '2 to 7 days'
15               when time1 between 8 and 15 then '8 to 15 days'
16               else 'not matching'
17          end "update time"
18     from (
19              select id, to_number(regexp_substr(time1, '^[[:digit:]]*')) time1
20                from t
21          )
22  /
        ID      TIME1 update time
        12          1 1 day
        23        244 not matching
        12          2 2 to 7 days
        14          4 2 to 7 days
        15          6 2 to 7 days
        17          9 8 to 15 days
6 rows selected.