datetime - Convert epoch to date in sqlplus / Oracle

Question

I have the following table:

SQL> desc recording
 Name                 Null?    Type
 -------------------- -------- ------
 CAPTUREID            NOT NULL NUMBER(9)
 STARTDATE            NOT NULL DATE
 ENDDATE                       DATE
 STATE                         NUMBER(1)
 ESTIMATEDENDTIME              NUMBER(13)

Here's a single line for this table:

SQL> select * from recording where CAPTUREID=14760457;

 CAPTUREID STARTDATE           ENDDATE             STATE ESTIMATEDENDTIME
---------- ------------------- ------------------- ----- ----------------
  14760457 29/09/2010 08:50:01 29/09/2010 09:52:04     0    1285746720000

I'm pretty sure that this has been asked so many times before, but all the solutions I've found so far didn't really work, so... How do I convert ESTIMATEDENDTIME from its original epoch form to a DD/MM/YYY HH:MI:SS format in a single query in SQLPLUS?

Thanks!

Answer 1

In Oracle, adding X to a DATE will return you a DATE X days later.

If ESTIMATEDENDTIME is milliseconds since Epoch then you could do

DATE '1970-01-01' + ( 1 / 24 / 60 / 60 / 1000) * ESTIMATEDENDTIME

and then use to_char to achieve the correct format of the resulting date. e.g:

SELECT 
  captureid
, startdate
, enddate
, state
, estimatedendtime
, DATE '1970-01-01' + ( 1 / 24 / 60 / 60 / 1000) * estimatedendtime AS estimatedenddate
FROM recording