12.4. RDB$TIME_ZONE_UTIL

A package of time zone utility functions and procedures.

12.4.1. Function DATABASE_VERSION

RDB$TIME_ZONE_UTIL.DATABASE_VERSION returns the version of the time zone database.

Return type:VARCHAR(10) CHARACTER SET ASCII.

Example 

select rdb$time_zone_util.database_version()
from rdb$database;

Returns:

DATABASE_VERSION
================
2023c

12.4.2. Procedure TRANSITIONS

RDB$TIME_ZONE_UTIL.TRANSITIONS returns the set of rules between the start and end timestamps for a named time zone.

Input parameters
RDB$TIME_ZONE_NAME

type CHAR(63) — The timezone name

RDB$FROM_TIMESTAMP

type TIMESTAMP WITH TIME ZONE — Start of date range

RDB$TO_TIMESTAMP

type TIMESTAMP WITH TIME ZONE — End of date range

Output parameters
RDB$START_TIMESTAMP

type TIMESTAMP WITH TIME ZONE — The start timestamp of the transition

RDB$END_TIMESTAMP

type TIMESTAMP WITH TIME ZONE — The end timestamp of the transition

RDB$ZONE_OFFSET

type SMALLINT — The zone’s offset, in minutes

RDB$DST_OFFSET

type SMALLINT — The zone’s DST offset, in minutes

RDB$EFFECTIVE_OFFSET

type SMALLINT — Effective offset (ZONE_OFFSET + DST_OFFSET)

Example 

select *
  from rdb$time_zone_util.transitions(
    'America/Sao_Paulo',
    timestamp '2017-01-01',
    timestamp '2019-01-01');

Returns (RDB$ prefix left off for brevity):

             START_TIMESTAMP                END_TIMESTAMP ZONE_OFFSET DST_OFFSET EFFECTIVE_OFFSET
============================ ============================ =========== ========== ================
2016-10-16 03:00:00.0000 GMT 2017-02-19 01:59:59.9999 GMT       -180        60             -120
2017-02-19 02:00:00.0000 GMT 2017-10-15 02:59:59.9999 GMT       -180         0             -180
2017-10-15 03:00:00.0000 GMT 2018-02-18 01:59:59.9999 GMT       -180        60             -120
2018-02-18 02:00:00.0000 GMT 2018-10-21 02:59:59.9999 GMT       -180         0             -180
2018-10-21 03:00:00.0000 GMT 2019-02-17 01:59:59.9999 GMT       -180        60             -120