Introduction to date and time data types

Time Series Analysis in PostgreSQL

Jasmin Ludolf

Content Developer, DataCamp

Date and time data types

Date, Time, DateTime data types

In PostgreSQL:

DATE : date data only
TIME : time information without time zone
TIMESTAMP : combines date and time without time zone
TIMESTAMPTZ : TIMESTAMP with time zones
INTERVAL : time between two points

Illustration of a calendar and a clock face.

Date and time values

DATE : YYYY-MM-DD (ISO 8601 international standard)
TIME : HH:MM:SS (seconds can be decimals, 12 or 24 hour clock)
TIMESTAMP : YYYY-MM-DD HH:MM:SS
TIMESTAMPTZ : YYYY-MM-DD HH:MM:SS+/-HH (+01:00 or CET)
INTERVAL : one input example is 1 02:30:04
- Interval of 1 day, 2 hours, 30 minutes, 4 seconds

Date and time in a table

CREATE TABLE timetable (
    date_info DATE,

    time_info TIMESTAMP,

    time_with_zone TIMESTAMPTZ,

    interval_length INTERVAL);

INSERT INTO timetable(
    date_info,

    time_info,

    time_with_zone,

    interval_length)

VALUES (
    'January 23 2013',

    '2023-01-20 18:00:00',

    '2023-01-20 18:00:00 EST',

    '1 02:03:04');

Date and time in a table

SELECT *
FROM timetable;

| date_info  | time_info           | time_with_zone            | interval_length |
| ---------- | ------------------- | ------------------------- | --------------- |
| 2023-01-20 | 2023-01-20 18:00:00 | 2023-01-20 00:00:00+01:00 | 1 day, 2:03:04  |

Partial or incorrect data

INSERT INTO timetable(time_info)
VALUES ('2020-02-20 12:00:00');

SELECT *
FROM timetable;

| date_info  | time_info           | time_with_zone            | interval_length |
| ---------- | ------------------- | ------------------------- | --------------- |
| 2023-01-20 | 2023-01-20 18:00:00 | 2023-01-20 00:00:00+01:00 | 1 day, 2:03:04  |
| null.      | 2020-02-20 12:00:00 | null                      | null            |

Partial or incorrect data

INSERT INTO timetable(time_info)
VALUES ('2020-02-20 02:00:00 EST');

SELECT *
FROM timetable;

| date_info  | time_info           | time_with_zone            | interval_length |
| ---------- | ------------------- | ------------------------- | --------------- |
| 2023-01-20 | 2023-01-20 18:00:00 | 2023-01-20 00:00:00+01:00 | 1 day, 2:03:04  |
| null.      | 2020-02-20 02:00:00 | null                      | null            |

Unix time

Unix time : seconds since the Unix epoch
Unix epoch : January 1 1970 00:00:00, UTC

|unix_time |
|----------|
|1483444800|

That's January 3 2017!

Let's practice!

Time Series Analysis in PostgreSQL