How to Get Epoch/UNIX Timestamp in MySQL

In MySQL, you can get Epoch timestamps using various functions and expressions. This article explores different ways to retrieve Epoch timestamps in MySQL and provides practical use cases.

Using the UNIX_TIMESTAMP() Function

In MySQL, you can use the UNIX_TIMESTAMP() function to fetch the current Epoch timestamp. This function takes no arguments and returns the current timestamp in seconds since the Epoch.

Example SQL Query

To obtain the current Epoch timestamp using the UNIX_TIMESTAMP() function, you should execute the following SQL query in your MySQL database management tool or application:

SELECT UNIX_TIMESTAMP() AS current_epoch_timestamp;

The above query will return the current Epoch timestamp as the result, labeled as "current_epoch_timestamp."

Use Case 1: Logging Timestamps

To log data with timestamps, you can use the UNIX_TIMESTAMP() function to obtain the current timestamp and insert it into a database table. Here's an example SQL query:

INSERT INTO sensor_data (data, timestamp)
VALUES ('Sensor data reading...', UNIX_TIMESTAMP());

In this SQL query, we're inserting sensor data along with the current Epoch timestamp into a table called "sensor_data."

Use Case 2: Time Duration Calculation

If you need to measure the time taken for a task, you can use the UNIX_TIMESTAMP() function to record start and end times. Here's how you can calculate the time elapsed in seconds:

SET @start_time = UNIX_TIMESTAMP();

-- Perform a task or operation

SET @end_time = UNIX_TIMESTAMP();
SELECT @end_time - @start_time AS time_elapsed_seconds;

This SQL script records the start and end times using the UNIX_TIMESTAMP() function and then calculates the time elapsed in seconds.

Using the FROM_UNIXTIME() Function

The FROM_UNIXTIME() function in MySQL allows you to convert an Epoch timestamp into a human-readable date and time format.

Example SQL Query

To convert an Epoch timestamp into a readable date and time format using the FROM_UNIXTIME() function, execute the following SQL query:

SELECT FROM_UNIXTIME(1635350400) AS readable_timestamp;

The above query converts the Epoch timestamp "1635350400" into a human-readable date and time format.

Use Case 3: Expiry Timestamp for Cache

If you need to set an expiry timestamp for cache data, you can use the FROM_UNIXTIME() function to calculate the expiry time based on the current timestamp. Here's an example SQL query:

INSERT INTO cached_data (data, expiry_timestamp)
VALUES ('Cached data...', FROM_UNIXTIME(UNIX_TIMESTAMP() + 600));

In this SQL query, the current Epoch timestamp is obtained using UNIX_TIMESTAMP(), and then 600 seconds (10 minutes) are added to it to determine the cache expiry time. The data is inserted into a table called "cached_data."

Use Case 4: Event Scheduling

To schedule an event to occur in the future, you can use the UNIX_TIMESTAMP() function to calculate the event time. Here's an example SQL script:

SET @event_time = UNIX_TIMESTAMP() + 3600; -- 1 hour from now

WHILE UNIX_TIMESTAMP() < @event_time DO
    -- Waiting for the event to occur
END WHILE;

INSERT INTO event_log (event_description, event_timestamp)
VALUES ('Event occurred!', FROM_UNIXTIME(UNIX_TIMESTAMP()));

This SQL script calculates the event time, waits for the event to occur, and then logs the event description and timestamp into a table called "event_log."

These code examples illustrate how to get Epoch/UNIX timestamps in MySQL and showcase their applications in practical scenarios. Whether you need to log data with timestamps, calculate time durations, set cache expiry times, or schedule events, Epoch timestamps are useful tools in MySQL for time-related operations.