BETWEEN FUNCTION WITH IN A DECODE FUNTION IN A CURSOR

Question

The following below is my query..I have to get the hours,min and seconds from a 'yyyy-mm-dd-24hh.mi.ss' value and check if the time is between 12 am to 6 am , then write it with one value else write an another value..I am trying to use 'BETWEEN' function in decode function but i am getting error.....Can we use BETWEEN function with in decode function or is there any other way
set serveroutput on
declare
cursor cur_dte is select lst_upd_date from EMPLOYESS ;
begin
for i in cur_dte loop
DECODE (substr(trim(i.lst_upd_date),12)) ,between '00.00.00.0000' and '06.00.00.00.0000' ,101,102);
dbms_output.put_line(i.lst_upd_date);
end loop;
end

Answer 1

First of all. If you are in PL/SQL then CASE is just a more colmplex expression then IF THEN ELSE. I usually prefere If then else, but for some rare cases.
The other issue is that you convert a datetime value into a string. This is wrong. it opens up all possible kinds of cenversion bugs. Stay with date or timestamp as long as possible.
The solution depends a little upon the datatype of your lst_upd_date column.
Here is a pl/sql solution assuming it is DATE.
The TRUNC function can be used to reduce a datetime to a day or to an hour.
declare
   cursor cur_dte is select lst_upd_date from employees ;
begin
   for i in cur_dte loop
     if trunc(i.lst_upd_date,'HH') between trunc(i.lst_upd_date) and trunc(i.lst_upd_date)+6/24 then
        dbms_output.put_line(to_char(i.lst_upd_date,'DD-MON-YYYY HH24:MI:SS'));
     end if;       
   end loop;
end;
/But a pure SQL solution is much better.
Here is how you implement it using CASE in SQL.
example using pure sql
select e.*,
        case when trunc(e.lst_upd_date,'HH')
               between trunc(e.lst_upd_date) and trunc(e.lst_upd_date)+6/24
        then 101
        else 102
        end as "early_morning_check"
from employees e;And if it is a timestamp column then you could use the EXTRACT function.
select e.*,
        case when to_number(extract(hour from e.lst_upd_date))
               between 0 and 6
        then 101
        else 102
        end as "early_morning_check"
from employees e;You might want to consider if date values like 06:45:00 should be included or not.