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SELECT * FROM pg_timezone_names WHERE name = current_setting('TIMEZONE');
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foo=> SET TIMEZONE TO 'Japan';
SET
foo=> SELECT '2011-01-01 00:00:00'::TIMESTAMP;
timestamp
---------------------
2011-01-01 00:00:00
(1 row)
foo=> SELECT '2011-01-01 00:00:00'::TIMESTAMP WITH TIME ZONE;
timestamptz
------------------------
2011-01-01 00:00:00+09
(1 row)
foo=> SELECT '2011-01-01 00:00:00+03'::TIMESTAMP;
timestamp
---------------------
2011-01-01 00:00:00
(1 row)
foo=> SELECT '2011-01-01 00:00:00+03'::TIMESTAMP WITH TIME ZONE;
timestamptz
------------------------
2011-01-01 06:00:00+09
(1 row)
foo=> SET TIMEZONE TO 'Australia/Melbourne';
SET
foo=> SELECT '2011-01-01 00:00:00'::TIMESTAMP;
timestamp
---------------------
2011-01-01 00:00:00
(1 row)
foo=> SELECT '2011-01-01 00:00:00'::TIMESTAMP WITH TIME ZONE;
timestamptz
------------------------
2011-01-01 00:00:00+11
(1 row)
foo=> SELECT '2011-01-01 00:00:00+03'::TIMESTAMP;
timestamp
---------------------
2011-01-01 00:00:00
(1 row)
foo=> SELECT '2011-01-01 00:00:00+03'::TIMESTAMP WITH TIME ZONE;
timestamptz
------------------------
2011-01-01 08:00:00+11
(1 row)
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select name from pg_timezone_names where name not like 'posix%' and name not ilike 'system%' order by name;
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-- You have an issue where entries in the database are recorded in local time without the timezone
-- Postgresql assumes that these entries are in fact UTC
-- This corrects these entries by converting them to actual UTC
-- You might want to update the column (from timestamp) to a timestamptz, then perform the command below
UPDATE <table>
SET <timestamptz_field> =
(<timestamptz_field> AT TIME ZONE 'UTC') AT TIME ZONE '<correct_time_zone>';
-- e.g start_date_time before = '2021-07-29 18:15:16+00' (This is from a location at GMT+2)
-- start_date_time after = '2021-07-29 16:15:16+00' (This is the actual UTC timestamp)
UPDATE public.uut_result
SET start_date_time= (start_date_time at time zone 'utc') at time zone 'Africa/Harare'