Converting XML date (ISO-8601) into timestamp in Oracle - oracle

Could you please help me in converting date time of format from "2015-02-23T16:26:41.485+05:30" to "23-FEB-15 16.26.41.000000000 AM" in Oracle.
I have an ISO-8601 date string in variable:
START_TIME='2015-02-23T16:26:41.485+05:30'
When I use
to_timestamp(START_TIME,'yyyy-mm-dd"T"hh24:mi:ss.ff3')
I get:
Error report:
ORA-01830: date format picture ends before converting entire input string
ORA-06512: at line 55
01830. 00000 - "date format picture ends before converting entire input string"
*Cause:
*Action:

To convert your string to a timestamp with time zone value, you need the to_timestamp_tz() function:
select to_timestamp_tz('2015-02-23T16:26:41.485+05:30',
'yyyy-mm-dd"T"hh24:mi:ss.ff3tzh:tzm') as result
from dual;
RESULT
-----------------------------------
2015-02-23 16:26:41.485000 +05:30
This includes the TZH and TZM datetime format model elements to handle the time zone offset; those can't be used in to_timestamp() or to_date() as those data types don't understand time zones.
You seem to want to lose the fractional seconds part, and the time zone information; you can achieve both at once by casting to a timestamp (without timezone) with the fractional seconds precision set to zero:
select cast(to_timestamp_tz('2015-02-23T16:26:41.485+05:30',
'yyyy-mm-dd"T"hh24:mi:ss.ff3tzh:tzm') as timestamp(0)) as result
from dual;
RESULT
-----------------------------------
2015-02-23 16:26:41.000000
But losing the time zone seems dangerous, unless you are sure that the data you receive is always going to be in the same time zone as your database. If you might have different time zones in the data but for some reason don't want to retain that information, you can also convert to a specific time zone for storage, but it isn't clear whether you need or want that here. If you aren't keeping the time zone or the fractional seconds, you may be better off with a date anyway.
Dates and timestamps do not have any inherent format within the database. If you then want to see that converted back into a string in the format you specified, pass it back into a to_char() call with the formatting you want; but as your example has both a 24-hour-clock hour value and an (incorrect) AM/PM indicator that isn't clear either. Maybe you want:
select to_char(cast(to_timestamp_tz('2015-02-23T16:26:41.485+05:30',
'yyyy-mm-dd"T"hh24:mi:ss.ff3tzh:tzm') as timestamp(0)),
'dd-MON-rr hh:mi:ss.ff9 am') as result
from dual;
RESULT
-----------------------------------
23-FEB-15 04:26:41.000000000 PM
To store the value from your START_TIME variable in a timestamp column the approach is exactly the same, just use that instead of the fixed value I've used above to demonstrate the conversion:
cast(to_timestamp_tz(START_TIME, 'yyyy-mm-dd"T"hh24:mi:ss.ff3tzh:tzm')
as timestamp(0))

Related

Change timestamp format in oracle

I am getting timestamp format as '01-APR-21 12.02.00.496677000 AM' from oracle, I want to change the format to load data into sql server column with datatype as datetime.
Current Input: '01-APR-21 12.02.00.496677000 AM'
Expected Output : 2021-04-01 12:02:00.496
I need to write the code in oracle to change timestamp format
Thanks
Neha
A TIMESTAMP is a binary data format consisting of 7-20 bytes (century, year-of-century, month, day, hour, minute, second, up to 6 bytes for fractional seconds and up to 7 bytes for time zone information); it does NOT have a format.
Why am I seeing the TIMESTAMP with a format?
You are seeing it with a format because whatever user interface you are using to access the database has decided that it is more useful to display the binary information as a formatted string rather than returning the raw byte values to you.
Typically, for SQL/Plus and SQL Developer, this is managed by the NLS_TIMESTAMP_FORMAT session parameter. Other user interfaces will have different mechanisms by which they manage the default format of dates and timestamps.
If you want to change the default for SQL/Plus (and SQl Developer) then you can use:
ALTER SESSION SET NLS_TIMESTAMP_FORMAT = 'YYYY-MM-DD HH24:MI:SS.FF9';
(Or whatever format you would like.)
How can I format the TIMESTAMP value?
If you then want to display the timestamp with a format (remember, a TIMESTAMP is not stored with any format) then you want to use TO_CHAR to convert it to a string where it can have a format.
If you want to format the TIMESTAMP as a YYYY-MM-DD HH24:MI:SS.FF3 string then use:
SELECT TO_CHAR( your_timestamp_column, 'YYYY-MM-DD HH24:MI:SS.FF3' )
FROM your_table
How can I convert a formatted string back to a TIMESTAMP?
From your comment:
I loaded the oracle data into a different SQL table where date format was varchar and data got loaded as '01-APR-21 12.02.00.496677000 AM'
Use TO_TIMESTAMP:
SELECT TO_TIMESTAMP( your_string_column, 'DD-MON-RR HH12:MI:SS.FF9 AM' )
FROM your_table
(Note: that this will convert your string to a binary TIMESTAMP and then whatever user interface you are using will use its rules on how to display it; and if the default format it is using is DD-MON-RR HH12:MI:SS.FF9 AM then the query above will look like it has done nothing; it has, the UI is just implicitly converting it back to a string to display it.)

How to make a constraint on DATE FORMAT in ORACLE

say my usual Date format is '14-jan-2019' and i want my date to only be accepted as 'YYYY-MM-DD' how do i do that? and can i change jan to an actual number?
In my opinion, the right / correct way to do that is to declare your date column (or variable or whatever it is) as DATE, e.g.
create table test (date_column date);
or
declare
l_date_variable date;
begin
...
Doing so, you'd let the database take care about valid values.
You'd then be able to enter data any way you want, using any valid date format mask, e.g.
to_date('06.01.2020', 'dd.mm.yyyy')
date '2020-01-06'
to_date('2020-06-01', 'yyyy-dd-mm')
etc. - all those values would be valid.
A DATE data type has no format - it is stored internally as 7-bytes representing year (2 bytes) and month, day, hour, minute and second (1 byte each).
'14-JAN-2019' is not a date - it is a text literal.
If you want to store date values then use a DATE data type.
If you want to only accept strings of a specific format as input then in whatever user interface you use to talk to the database then accept only that format. If you are converting strings to DATEs and wanting an exact format then you can use:
TO_DATE( '2019-01-14', 'fxYYYY-MM-DD' )
Note: the fx format model will mean that the exact format is expected and the typical string-to-date conversion rules will not be applied.

Storing timestamp values stored in a varchar2 column into a date column in oracle

I have a column in a table that stores timestamp values as
"2018-01-12 16:13:51.107000000", i need to insert this column into a date column in another table, what format mask do i have to use here..
I have used the mask 'YYYY-MM-DD HH24:MI:SS.FF' but shows 'date format not recognized'.
I am assuming that you were trying to use TO_DATE on your text timestamp data. This won't work, because Oracle dates do not store anything more precise than seconds. Since your timestamps have fractional seconds, you may use TO_TIMESTAMP here, then cast that actual timestamp to a date:
SELECT
CAST(TO_TIMESTAMP('2018-01-12 16:13:51.100000',
'YYYY-MM-DD HH24:MI:SS.FF') AS DATE)
FROM dual;
12.01.2018 16:13:51
Demo
You can do this with a single call to TO_DATE(), but you must give the correct format model. Note that this solution is simpler (and possibly faster - if that matters) than converting to a timestamp and then casting to date.
If you want TO_DATE() to ignore part of the input string, you can use the "boilerplate text" syntax in the format model. That is enclosed in double quotes. For example, if your string included the letter T somewhere and it had to be ignored, you would include "T" in the same position in the format model.
This has some flexibility. In your case, you must ignore the decimal point, and up to nine decimal digits (the maximum for timestamp in Oracle). The format model will allow you to use ".999999999" (or any other digits, but 9999... is used by most programmers) to ignore a decimal point and UP TO nine digits after that.
Demo: (notice the double-quoted "boilerplate text" in the format model)
select to_date('2018-01-12 16:13:51.100000',
'YYYY-MM-DD HH24:MI:SS".999999999"') as dt
from dual;
DT
-------------------
2018-01-12 16:13:51

How to Insert a Timestamp in Oracle in a Specific Format

I am at a loss as how to insert the current time in a different format than the default. Can somebody help explain?
Here is how my table was created:
CREATE TABLE ACTIVITY_LOG
(
TIME TIMESTAMP NOT NULL
, ACTIVITY VARCHAR2(200) NOT NULL
);
My insert command works:
insert into activity_log
values (localtimestamp,'blah');
But how do i insert the localtimestamp value into my table in a different format using the various MM DD YY HH MM SS tags? I've tried the following, but it gives me the ORA-1830: date format picture ends before converting entire input string error.
insert into activity_log
values (to_timestamp(localtimestamp,'YYYY/MM/DD'),'blah');
You don't insert a timestamp in a particular format. Timestamps (and dates) are stored in the database using an internal representation, which is betwen 7 and 11 bytes depending on the type and precision. There is more about that in this question, among others.
Your client or application decides how to display the value in a human-readable string form.
When you do:
to_timestamp(localtimestamp,'YYYY/MM/DD')
you are implicitly converting the localtimestamp to a string, using your session's NLS settings, and then converting it back to a timestamp. That may incidentally change the value - losing precision - but won't change how the value is stored internally. In your case the mismatch between the NLS setting and the format you are supplying is leading to an ORA-01830 error.
So your first insert is correct (assuming you really want the session time, not the server time). If you want to see the stored values in a particular format then either change your client session's NLS settings, or preferably format it explicitly when you query it, e.g.:
select to_char(time, 'YYYY-MM-DD HH24:MI:SS.FF3') from activity_log
You don't seem to provide any indication of what your 'localtimestamp' is - is that pseudocode? A variable name? A column you haven't shown the definition for?
What data type is 'localtimestamp'? What data does it contain? Pertinent questions as other answers point out, because if it truly is a time stamp then oracle will be converting it to a string for you, before passing that string to to_timestamp() in your final query. Your initial stab at it should just work if the variable is a timestamp, containing a timestamp
Ultimately "date format picture ends" means "you passed me a string looking like '2017-05-17 12:45:59', but claimed it was only 'yyyy-mm-dd'. What was I expected to do with the rest of it?"
Your current final comment on your question "I was hoping to look in the table and see a useful looking time" - that's your query tool's problem. Have a look in the setting of your query tool and change the date format it displays. As has been noted, dates in oracle are stored as a decimal number days since a certain moment in time. If 0 represents 01 Jan 1970, then 1.75 represents 6pm on the 2 Jan 1970. It is up to the end program the user is using, to format the date into something you like.. you cannot "insert a timestamp with a different format" because time stamps don't have a format any more than a number like 1.75 has a format. It is what your query does with it when it gets it out, that gives it the format:
To_char(timestampcol, 'yyyy mm did')
To-char(tomestampcol, 'mon dd yyyy')
These use oracles built in date formatter, that turns that decimal number of the date into a string in the given format; you will see a string.. or you can just write "select * from table" and run it in TOAD and toad will show you the dates according to the format in settings, or you can write a c# program and get a load of date objects out and call my date.ToString("yyyy-MM-dd") on them to format them. The idea I'm trying to get across is that you don't pick the date format on the way in, you pick it on the way out, if you don't like what you're looking at, you have to change it on the way out, not the way in

How to change default date,timestamp dataype for columns in oracle

I have created a table in Oracle in which I have KPI_START_DATE column which is a Date datatype, and KPI_START_TIME which is a TIMESTAMP datatype.
Now I want to modify this date dataype for
KPI_START_DATE to dd/mm/yyyy
and
KPI_START_TIME to HH:MI:SS.
So that user should always enter the date and time in this column in this proper format.
I tried below query but its was giving error:
Alter table KPI_DEFINITION MODIFY(to_char(KPI_START_DATE,'dd/mm/yyyy') )
DATE and TIMESTAMP columns do not have any inherent readable format. The values are stored in Oracle's own internal representation, which has no resemblance to a human-readable date or time. At the point to retrieve or display a value you can convert it to whatever format you want, with to_char().
Both DATE and TIMESTAMP have date and time components (to second precision with DATE, and with fractional seconds with TIMESTAMP; plus time zone information with the extended data types), and you should not try to store them separately as two columns. Have a single column and extract the information you need at any time; to get the information out of a single column but split into two fields you could do:
select to_char(KPI_START, 'dd/mm/yyyy') as KPI_START_DATE,
to_char(KPI_START, 'hh24:mi:ss') as KPI_START_TIME
but you'd generally want both together anyway:
select to_char(KPI_START, 'dd/mm/yyyy hh24:mi:ss')
Also notice the 'hh24' format model to get the 24-hour clock time; otherwise you wouldn't see any difference between 3 a.m. and 3 p.m.
You can store a value in either type of column with the time set to midnight, but it does still have a time component - it is just midnight. You can't store a value in either type of column with just a time component - it has to have a date too. You could make that a nominal date and just ignore it, but I've never seen a valid reason to do that - you're wasting storage in two columns, and making searching for and comparing values much harder. Oracle even provides a default date if you don't specify one (first day of current month). But the value always has both a date and a time part:
create table KPI_DEFINITION (KPI_START date);
insert into KPI_DEFINITION (KPI_START)
values (to_date('27/01/2015', 'DD/MM/YYYY'));
insert into KPI_DEFINITION (KPI_START)
values (to_date('12:41:57', 'HH24:MI:SS'));
select to_char(KPI_START, 'YYYY-MM-DD HH24:MI:SS') from KPI_DEFINITION;
TO_CHAR(KPI_START,'YYYY-MM-DDHH24:MI:SS')
-----------------------------------------
2015-01-27 00:00:00
2015-01-01 12:41:57
Your users should be inserting a single value with both date and time as one:
insert into KPI_DEFINITION (KPI_START)
values (to_date('27/01/2015 12:41:57', 'DD/MM/YYYY HH24:MI:SS'));
select to_char(KPI_START, 'YYYY-MM-DD HH24:MI:SS') from KPI_DEFINITION;
TO_CHAR(KPI_START,'YYYY-MM-DDHH24:MI:SS')
-----------------------------------------
2015-01-27 12:41:57
You can also use date or timestamp literals, and if using to_date() you should always specify the full format - don't rely on NLS settings as they may be different for other users.
You should understand difference between datatype and format. DATE is a datatype. TIMESTAMP is a datatype. None of them have formats, they're just numbers.
When converting character datatype to or from date datatype, format should be applied. It's an attribute of an actual conversion, nothing else.
Look at this:
SQL> create table tmp$date(d date);
Table created
SQL> insert into tmp$date values (DATE '2010-11-01');
1 row inserted
SQL> insert into tmp$date values (DATE '2014-12-28');
1 row inserted
SQL> select d, dump(d) from tmp$date;
D DUMP(D)
----------- ---------------------------------
01.11.2010 Typ=12 Len=7: 120,110,11,1,1,1,1
28.12.2014 Typ=12 Len=7: 120,114,12,28,1,1,1
There is no any 'format' here.
DISPLAYING and STORING are NOT the same when it comes to DATE.
When people say Oracle isn’t storing the date in the format they wanted, what is really happening is Oracle is not presenting the date in the character string format they expected or wanted.
When a data element of type DATE is selected, it must be converted from its internal, binary format, to a string of characters for human consumption. The conversion of data from one type to another is known as known a “conversion”, “type casting” or “coercion”. In Oracle the conversion between dates and character strings is controlled by the NLS_DATE_FORMAT model. The NLS_DATE_FORMAT can be set in any of several different locations, each with its own scope of influence.
I could go on with my leacture over DATE data type, but I am glad that someone has already got a good writeup over this. Please read this https://edstevensdba.wordpress.com/2011/04/07/nls_date_format/

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