Postgres 14

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CREATE TABLE conditions (
    time        TIMESTAMPTZ       NOT NULL,
    location    TEXT              NOT NULL,
    temperature DOUBLE PRECISION  NULL,
    humidity    DOUBLE PRECISION  NULL,
    UNIQUE (time, location)
);

CREATE UNIQUE INDEX on conditions (time, location);

INSERT INTO conditions
  VALUES ('2017-07-28 11:42:42.846621+00', 'office', 60.1, 50.0);
1 rows affected

SELECT * FROM conditions;


time
location
temperature
humidity


2017-07-28 12:42:42.846621+01
office
60.1
50


INSERT INTO conditions VALUES ('2017-07-28 11:42:42.846621+00', 'office', 70.2, 50.1);
ERROR:  duplicate key value violates unique constraint "conditions_time_location_key"
DETAIL:  Key ("time", location)=(2017-07-28 12:42:42.846621+01, office) already exists.


INSERT INTO conditions VALUES ('2017-07-28 11:42:42.846621+00', 'office', 70.2, 50.1)
  ON CONFLICT DO NOTHING;
SELECT * FROM conditions;


time
location
temperature
humidity


2017-07-28 12:42:42.846621+01
office
60.1
50


INSERT INTO conditions VALUES ('2017-07-28 11:42:42.846621+00', 'office', 70.2, 50.1)
  ON CONFLICT (time, location) DO UPDATE
    SET humidity = excluded.temperature;
1 rows affected

SELECT * FROM conditions;


time
location
temperature
humidity


2017-07-28 12:42:42.846621+01
office
60.1
70.2