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TIMESTAMP related Oracle SQL functions

FROM_TZ

select
           timestamp '2023-08-05 18:17:16'                    ts,
   from_tz(timestamp '2023-08-05 18:17:16', 'Europe/Zurich')  ts_zrh
from
   dual;
--
-- TS                            TS_ZRH                                     
-- ----------------------------- -------------------------------------------
-- 2023-08-05 18.17.16.000000000 2023-08-05 06.17.16.000000000 EUROPE/ZURICH

ADJ_DATE

The undocumented function adj_date round (truncates) a timestamp down to a non-fractional second.
create table tq84_t (
   ts  timestamp
);

insert into tq84_t values (systimestamp);

select
   ts,
   adj_date(ts)  ts_
from
   tq84_t;
--
-- TS                            TS_                          
-- ----------------------------- -----------------------------
-- 2022-02-23 18:46:58.658000000 2022-02-23 18:46:59.000000000

drop table tq84_t;
It seems that the function can only be used when applied on a column value. The following statement throws a ORA-00932: inconsistent datatypes: expected DATE got TIMESTAMP WITH TIME ZONE error.
select
   adj_date(systimestamp)
from
   dual;

See also

Oracle SQL functions

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