PostgreSQL REAL Data Type

Summary: in this tutorial, you will learn how to use the PostgreSQL REAL data type to store single-precision floating-point numbers in the database.

Introduction to the PostgreSQL REAL data type

The REAL data type allows you to store single-precision floating-point numbers in the database.

A value of the real type takes 4 bytes of storage space. Its valid range is from -3.40282347 × 1038 and 3.40282347 × 1038.

Typically, you use the REAL data type to store floating-point numbers with relatively large ranges and precision is not critical, or when you are concerned about the storage space.

However, you can use the double precision data type if you need higher precision.

PostgreSQL REAL data type example

First, create a table called weathers to store wind speed (meter per second) and temperature (celsius) data:

CREATE TABLE weathers(
    id INT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    location VARCHAR(255) NOT NULL,
    wind_speed_mps REAL NOT NULL,
    temperature_celsius REAL NOT NULL,
    recorded_at TIMESTAMP NOT NULL
);

Second, insert rows into the weathers table:

INSERT INTO weathers (location, wind_speed_mps, temperature_celsius, recorded_at)
VALUES
    ('New York', 5.2, 15.3, '2024-04-19 09:00:00'),
    ('New York', 4.8, 14.9, '2024-04-19 10:00:00'),
    ('New York', 6.0, 16.5, '2024-04-19 11:00:00'),
    ('New York', 5.5, 15.8, '2024-04-19 12:00:00'),
    ('New York', 4.3, 14.2, '2024-04-19 13:00:00'),
    ('New York', 5.9, 16.1, '2024-04-19 14:00:00'),
    ('New York', 6.8, 17.3, '2024-04-19 15:00:00'),
    ('New York', 5.1, 15.6, '2024-04-19 16:00:00'),
    ('New York', 4.7, 14.8, '2024-04-19 17:00:00'),
    ('New York', 5.3, 15.9, '2024-04-19 18:00:00');

Third, calculate the average wind speed and temperature in New York on April 19, 2024:

SELECT
  AVG(wind_speed_mps)       wind_speed,
  AVG(temperature_celsius) temperature_celsius
FROM
  weathers
WHERE
  location = 'New York'
  AND DATE(recorded_at) = '2024-04-19';

Output:

wind_speed     | temperature_celsius
-------------------+---------------------
 5.360000038146973 |  15.639999961853027
(1 row)

Summary

Use the PostgreSQL REAL data type to store single-precision floating-point numbers in the database.