[sql] How to change the date format from MM/DD/YYYY to YYYY-MM-DD in PL/SQL?

I have a date column in a table stored as MM/DD/YYYY format. I have to select and store the same date in another table in YYYY-MM-DD format i.e. XSD Date Format. But I am not able to do it. I am using this query:

select to_date(date_column,'YYYY-MM-DD') from table;

But still I am not able to do it. Giving me error

ORA-01843 : not a valid month

select to_date(to_char(ORDER_DATE,'YYYY/MM/DD')) 
from ORDERS;

This might help but, at the end you will get a string not the date. Apparently, your format problem will get solved for sure .

use

SELECT STR_TO_DATE(date_column,'%Y-%m-%d') from table;

also gothrough

http://dev.mysql.com/doc/refman/5.0/en/date-and-time-functions.html

It sounds like you've got it the wrong way round. If your existing data is in MM/DD/YYYY format, then you want:

select to_date(date_column,'MM/DD/YYYY') from table;

to convert the existing data to DATE values. (I do wonder why they're not stored as dates, to be honest...)

If you want to perform the conversion in one step, you might want:

select to_char(to_date(date_column,'MM/DD/YYYY'), 'YYYY-MM-DD') from table;

In other words, for each row, parse it in MM/DD/YYYY format, then reformat it to YYYY-MM-DD format.

(I'd still suggest trying to keep data in its "natural" type though, rather than storing it as text in the first place.)

According to the comments, the data-type in the datatable is DATE. So you should simply use: "select date_column from table;"

Now if you execute the select you will get back a date data-type, which should be what you need for the .xsd.

Culture-dependent formating of the date should be done in the GUI (most languages have convenient ways to do so), not in the select-statement.

if you need to change your column output date format just use to_char this well get you a string, not a date.

You can do this simply by :

select to_char(to_date(date_column, 'MM/DD/YYYY'), 'YYYY-MM-DD') from table

use

select to_char(date_column,'YYYY-MM-DD') from table;

I assume that you can use the Oracle SQL Developer, which you can download from here.

You can define the date format which you want to work with:

ALTER SESSION SET nls_date_format='yyyy-mm-dd';

With this, now you can perform a query like this:

SELECT * FROM emp_company WHERE JDate = '2014-02-25'

If you want to be more specific you can define the date format like this:

ALTER SESSION SET nls_date_format='yyyy-mm-dd hh24:mi:ss';

Late reply but for.databse-date-type the following line works.

SELECT to_date(t.given_date,'DD/MM/RRRR') response_date FROM Table T

given_date's column type is Date

Basically , Data in a Date column in Oracle can be stored in any user defined format or kept as default. It all depends on NLS parameter.

Current format can be seen by : SELECT SYSDATE FROM DUAL;

If you try to insert a record and insert statement is NOT in THIS format then it will give : ORA-01843 : not a valid month error. So first change the database date format before insert statements ( I am assuming you have bulk load of insert statements) and then execute insert script.

Format can be changed by : ALTER SESSION SET nls_date_format = 'mm/dd/yyyy hh24:mi:ss';

Also You can Change NLS settings from SQL Developer GUI , (Tools > preference> database > NLS)

Ref: http://oracle.ittoolbox.com/groups/technical-functional/oracle-sql-l/how-to-view-current-date-format-1992815

For military time formatting,

select TO_CHAR(SYSDATE, 'yyyy-mm-dd hh24:mm:ss') from DUAL

--2018-07-10 15:07:15

If you want your date to round DOWN to Month, Day, Hour, Minute, you can try

SELECT TO_CHAR( SYSDATE, 'yyyy-mm-dd hh24:mi:ss') "full-date" --2018-07-11 10:40:26
, TO_CHAR( TRUNC(SYSDATE, 'year'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-year"-- 2018-01-01 00:00:00
, TO_CHAR( TRUNC(SYSDATE, 'month'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-month" -- 2018-07-01 00:00:00
, TO_CHAR( TRUNC(SYSDATE, 'day'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-Sunday" -- 2018-07-08 00:00:00
, TO_CHAR( TRUNC(SYSDATE, 'dd'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-day" -- 2018-07-11 00:00:00
, TO_CHAR( TRUNC(SYSDATE, 'hh'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-hour" -- 2018-07-11 10:00:00
, TO_CHAR( TRUNC(SYSDATE, 'mi'), 'yyyy-mm-dd hh24:mi:ss') "trunc-to-minute" -- 2018-07-11 10:40:00
from DUAL

For formats literals, you can find help in https://docs.oracle.com/cd/B28359_01/server.111/b28286/functions242.htm#SQLRF52037

To convert a DATE column to another format, just use TO_CHAR() with the desired format, then convert it back to a DATE type:

SELECT TO_DATE(TO_CHAR(date_column, 'DD-MM-YYYY'), 'DD-MM-YYYY') from my_table

SELECT TO_DATE(TO_CHAR(date_column,'MM/DD/YYYY'), 'YYYY-MM-DD')
FROM table;

This worked for me! You can convert to datatype you want be it a date or string

to_char(TO_DATE(TO_CHAR(end_date),'MM-DD-YYYY'),'YYYY-MM-DD') AS end_date