Konverter lokal datotid (med tidszone) til et Unix-tidsstempel i Oracle

Du kan konvertere dit tidsstempel med tidszone til UTC og derefter trække epoken fra det:

select timestamp '2018-10-19 09:12:47.0 AMERICA/DENVER'
  - timestamp '1970-01-01 00:00:00.0 UTC' as diff
from dual;

som giver dig en intervaldatatype:

DIFF                  
----------------------
+17823 15:12:47.000000

Du kan derefter udtrække elementerne fra det og gange hvert element med en passende faktor for at konvertere det til millisekunder (dvs. for dage, 60*60*24*1000); og føj dem derefter sammen:

select extract(day from diff) * 86400000
  + extract(hour from diff) * 3600000
  + extract(minute from diff) * 60000
  + extract(second from diff) * 1000 as unixtime
from (
  select timestamp '2018-10-19 09:12:47.0 AMERICA/DENVER'
    - timestamp '1970-01-01 00:00:00.0 UTC' as diff
  from dual
);

            UNIXTIME
--------------------
       1539961967000

db<>violin

Dette bevarer også millisekunder, hvis starttidsstemplet har dem (dette konverteres fra en 'Unix'-tid, mens de bevares):

select (timestamp '1970-01-01 00:00:00.0 UTC' + (1539961967567 * interval '0.001' second))
  at time zone 'America/Denver' as denver_time
from dual;

DENVER_TIME                                 
--------------------------------------------
2018-10-19 09:12:47.567000000 AMERICA/DENVER

derefter for at konvertere tilbage:

select extract(day from diff) * 86400000
  + extract(hour from diff) * 3600000
  + extract(minute from diff) * 60000
  + extract(second from diff) * 1000 as unixtime
from (
  select timestamp '2018-10-19 09:12:47.567 AMERICA/DENVER'
    - timestamp '1970-01-01 00:00:00.0 UTC' as diff
  from dual
);

            UNIXTIME
--------------------
       1539961967567

db<>fiddle

Hvis dit starttidsstempel har større præcision end det, bliver du nødt til at afkorte (eller runde/gulv/loft/støbning) for at undgå at få et resultat uden heltal; denne version trunkerer bare den udtrukne millisekunders del:

select diff,
  extract(day from diff) * 86400000
  + extract(hour from diff) * 3600000
  + extract(minute from diff) * 60000
  + trunc(extract(second from diff) * 1000) as unixtime
from (
  select timestamp '2018-10-19 09:12:47.123456789 AMERICA/DENVER'
    - timestamp '1970-01-01 00:00:00.0 UTC' as diff
  from dual
);

DIFF                                  UNIXTIME
------------------------- --------------------
+17823 15:12:47.123456789        1539961967123

Uden den trunkering (eller tilsvarende) ville du ende med 1539961967123.456789 .

Jeg havde glemt uoverensstemmelsen i springsekunder; hvis du har brug for/ønsker at håndtere det, se dette svar .