Update existing date field

Question

select date1, arrtime, deptime,
CASE WHEN arrdep = 'A' then
to_date(to_char(date1, 'dd/mm/yyyy')||to_char(to_date(arrtime, 'hh24:mi'), 'hh24:mi'), 'dd/mm/yyyy hh24:mi')
ELSE to_date(to_char(date1, 'dd/mm/yyyy')||to_char(to_date(deptime, 'hh24:mi'), 'hh24:mi'), 'dd/mm/yyyy hh24:mi')
END as DepArr from table1
output
====
date1 arrtime deptime DepArr
2005/10/25 0 0830 2005/10/25 08:30:00
2005/10/27 2215 0 2005/10/27 22:15:00
when i use the above select statement, the output displays fine, but when i tried to update the date1 field with DepArr, it fails with ORA-01861
update table1 set date1 =
CASE WHEN arrdep = 'A' then
to_date(to_char(dt, 'dd/mm/yyyy')||to_char(to_date(arrtime, 'hh24:mi'), 'hh24:mi'), 'dd/mm/yyyy hh24:mi')
ELSE to_date(to_char(dt, 'dd/mm/yyyy')||to_char(to_date(deptime, 'hh24:mi'), 'hh24:mi'), 'dd/mm/yyyy hh24:mi')
END
the date1 field's datatype is date
thanks.

Answer 1

As far as I can see, your select can be simplified to:
select date1, arrtime, deptime,
to_date(to_char(date1, 'ddmmyyyy')||decode(arrdep, 'A', arrtime, deptime), 'ddmmyyyyhh24mi') as DepArr
from table1Make sure that date1 and arrtime/deptime is not null otherwise to_date will fail
Message was edited by:
Jens Petersen