UNIX timestamp to Oracle Date Conversion

Earlier today a situation came up where a UNIX timestamp (a count of the number of seconds from January 1, 1970, midnight GMT) needed to be converted into an Oracle DATE format. The Oracle TO_DATE (covered in more detail in my article Oracle, SQL, Dates and Timestamps) does not support this type of conversion.

A Google search confirmed for me that their was no easy way to make the TO_DATE function do this, but I did find this article from the Oracle + PHP Cookbook on Oracle’s site which contained this simple function to convert UNIX timestamps to Oracle dates.

* Converts a UNIX timestamp into an Oracle DATE
unix_epoch DATE := TO_DATE(‘19700101000000′,’YYYYMMDDHH24MISS’);
max_ts PLS_INTEGER := 2145916799; — 2938-12-31 23:59:59
min_ts PLS_INTEGER := -2114380800; — 1903-01-01 00:00:00
oracle_date DATE;


IF unixts > max_ts THEN
‘UNIX timestamp too large for 32 bit limit’
ELSIF unixts < min_ts THEN RAISE_APPLICATION_ERROR( -20901, 'UNIX timestamp too small for 32 bit limit' ); ELSE oracle_date := unix_epoch + NUMTODSINTERVAL(unixts, 'SECOND'); END IF; RETURN (oracle_date); END; / [/SQL] Once compiled, you can use the function to convert numerical UNIX timestamps into Oracle dates in the same manner you would use the TO_DATE function to convert text to dates. Here is an example: SQL> select unixts_to_date(1094165422) from dual;


oracle, sql, dba, database administration, database development, unix, unix timestamp, timestamp

14 thoughts on “UNIX timestamp to Oracle Date Conversion”

  1. whenever i execute this procedure, it give following error

    ——– —————————————————————–
    22/17 PL/SQL: Statement ignored
    22/45 PLS-00201: identifier ‘NUMTODSINTERVAL’ must be declared

    I am using
    Oracle8i Enterprise Edition Release – Production
    With the Partitioning option
    JServer Release – Production

    SQL*Plus: Release

    please respond ASAP

  2. Ambrish, for some reason the user you are trying to run this as cannot see the function, or you are using the function improperly.

    Did you get any errors after compiling the function?

    Are you connecting as the same user who created the function? If not you will need to creat a public synonym for the function and grant execute to the users who will need it.

  3. It seems the NUMTODSINTERVAL function is new in Oracle 9i. If you are working with Oracle 8i or earlier you can substitute this line:

    oracle_date := unix_epoch + (unixts/86400);

    instead of the NUMTODSINTERVAL to eliminate this error.

    The NUMTODSINTERVAL function turns the number of seconds into a fractional number representing days. Dividing the seconds by 86400 (the number of seconds in 1 day) achieves the same thing.

  4. That’s a nice and succinct method Johannes. The one above does essentially the same thing with a couple variables and a couple more steps, but also provides some exception handling.

  5. I thought it will solve the problem , but its not.
    I implemented the same procedure what ever is given above for converting from timestamp to date and time . It is giveing the correct date but not the time , as my sytem is showing it differently

  6. Srivalli,

    I believe the discrepency you are seing is because the UNIX timestamp is reported in Coordinated Universal Time (UTC). UTC is equivalent to Greenwich Mean Time (GMT). To evaluate the date in your local timezone you will need to convert it with the Oracle delivered new_time function as below:

    select to_char(new_time(unixts_to_date(1145366808), ‘GMT’, ‘EDT’), ‘MM/DD/YYYY HH24:MI:SS’) from dual

    If you grab a UNIX timestamp from a converter on a website be careful, some of them are converting for their own timezone already. This one allows you to enter an offset from GMT for accurate timestamps:


    Hope this helps. Perhaps I’ll rewrite this function to compensate for the timezone as well.


  7. This query converts UNIX to Oracle and handles the time zones. Add TO_CHAR to format the date, if required.

    select trunc((timestamp ‘1970-01-01 00:00:00 GMT’ + numtodsinterval(1094165422, ‘SECOND’)) at time zone ‘Canada/Pacific’) at_time_zone_date
    from dual

  8. Yup, Mike’s query does the same thing my function does, just without error handling. Nice for a one-off but if you need this often it’s handy to have the function around.


  9. What to do if my timestamps are bigger that 32-bit format e.g. 1026259200000 for date 2002-07-10 (yyyy-MM-dd)? If I cut last free 0 I’m getting correct date. But how can be sure when to cut them and when not?

  10. Hi,

    I need to select timestamp from one of DB tables,but it is in unix tistamp format.How can i convert unix timestamp to normal dd/mm/yyyy and select the data in oracle.

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