I'm trying to convert string column to date in Oracle SQL.
Here is my an example of value from the data:
'03/12/14 11:00:00'
Here is my query:
select to_date(A,'DD/MM/YY HH24:MI:SS')
from MyTable
Here is an example of the output:
03-DEC-14
Why my query return only the date but not the hour?
Assuming you are using SQL*Plus (or SQL Developer) the default NLS_DATE_FORMAT is applied when a DATE value is displayed. To verify your current format you can run:
select value
from nls_session_parameters
where parameter = 'NLS_DATE_FORMAT';
To adjust this, run:
alter session set nls_date_format = 'YYYY-MM-DD HH24:MI:SS';
Then you should see the time as well.
You are trying to DISPLAY the datetime value. Use TO_CHAR along with proper FORMAT MODEL.
For example,
select to_char(sysdate, 'mm/dd/yyyy hh24:mi:ss') from dual;
A DATE consists of both date and time portions. You just need to make sure you use appropriate format model to display it. Else, you end up with a format which depends on your locale-specific NLS settings.
You can use timestamp
select to_timestamp(A, 'DD/MM/YY HH24:MI:SS') from MyTable
If you want a query that returns the time portion of the date without having to alter the nls_date_format you can convert the date you got from the to_date function to a text representation (the default text representation is dd-Mon-yy as you found out) like this:
select to_char(
to_date(A,'DD/MM/YY HH24:MI:SS'),
''DD/MM/YY HH24:MI:SS')
from MyTable;
Ideally, column A of MyTable should have been defined as a date column instead of a varchar2 column. There are several reasons to do that; data integrity, and better SQL optimization.
datedoes have a time.