MySQL 5.7

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select version();


version()


5.7.35


SELECT @@session.time_zone, NOW();

-- 
-- As of 27/12/2021, the db<>fiddle server uses the SYSTEM timezone which, given that
-- it's located in Britain is either UTC (in winter) or UTC+1 (summer). So, setting a
-- timezone of +07 should give clear blue water between the zones for the purposes of
-- this test. The example given of Utah in the US should retain a 7 hour difference
-- because, for the moment at least, they also have Daylight Savings Time (DST)
--


@@session.time_zone
NOW()


SYSTEM
2022-05-09 18:22:57


SET time_zone = "+07:00";
SELECT @@session.time_zone, NOW();


@@session.time_zone
NOW()


+07:00
2022-05-10 00:22:57


CREATE TABLE testx 
(
  d DATETIME,
  t TIMESTAMP(6)
);
INSERT INTO testx VALUES (NOW(6), NOW(6));
SELECT * FROM testx;


d
t


2022-05-10 00:22:58
2022-05-10 00:22:57.562008


SET time_zone = "+00:00";
SELECT 
  UNIX_TIMESTAMP(d) AS "DateTime", UNIX_TIMESTAMP(t) AS "TimeStamp", 
  UNIX_TIMESTAMP(NOW(6)) AS "Now",
  SEC_TO_TIME(UNIX_TIMESTAMP(d) - UNIX_TIMESTAMP(NOW())) AS "DT diff", -- = 7 hours (+ rounding)
  SEC_TO_TIME(UNIX_TIMESTAMP(t) - UNIX_TIMESTAMP(NOW())) AS "TS diff", -- few deciseconds 
  FROM_UNIXTIME(UNIX_TIMESTAMP(t)) AS "Now wall time here",                 -- = queries above
  FROM_UNIXTIME(UNIX_TIMESTAMP(d)) AS "Now wall +7 (e.g. Utah, US relative to UTC)
                                                    \nSmall rounding difference?"
FROM testx;


DateTime
TimeStamp
Now
DT diff
TS diff
Now wall time here
Now wall +7 (e.g. Utah, US relative to UTC)
                                                    
Small rounding difference?


1652142178
1652116977.562008
1652116977.564732
07:00:01
00:00:00.562008
2022-05-09 17:22:57.562008
2022-05-10 00:22:58