Unix Timestamp in Postgres

Introduction

Unix Timestamp, also known as Epoch Timestamp, represents the number of seconds that have elapsed since January 1, 1970, 00:00:00 Coordinated Universal Time (UTC). It is a common way to store and manipulate date and time information in many programming languages and databases, including PostgreSQL.

In this guide, we will explore how to work with Unix Timestamps in PostgreSQL, including converting between Unix Timestamps and regular date/time formats, performing calculations, and querying using Unix Timestamps.

Converting Unix Timestamp to Regular Date/Time

To convert a Unix Timestamp to a regular date/time format in PostgreSQL, you can use the to_timestamp() function. Here's an example:

SELECT to_timestamp(1619534123);

This will return the corresponding date and time in a human-readable format like 2021-04-27 12:48:43+00. You can also format the output using to_char() function to display the date/time in a specific format. For example:

SELECT to_char(to_timestamp(1619534123), 'YYYY-MM-DD HH24:MI:SS');

This will return the timestamp as 2021-04-27 12:48:43.

Converting Regular Date/Time to Unix Timestamp

To convert a regular date/time to a Unix Timestamp in PostgreSQL, you can use the extract() function along with epoch keyword. Here's an example:

SELECT extract(epoch FROM TIMESTAMP '2021-04-27 12:48:43');

This will return the Unix Timestamp representation of the given date and time, such as 1619534123.

Performing Calculations with Unix Timestamps

PostgreSQL provides various functions to perform calculations with Unix Timestamps. Here are a few examples:

• Adding/Subtracting Seconds:

  SELECT to_timestamp(1619534123) + interval '1 second';
  SELECT to_timestamp(1619534123) - interval '1 second';
  

• Extracting Date/Time Components:

  SELECT EXTRACT(YEAR FROM to_timestamp(1619534123));
  SELECT EXTRACT(MONTH FROM to_timestamp(1619534123));
  SELECT EXTRACT(DAY FROM to_timestamp(1619534123));
  

• Comparing Unix Timestamps:

  SELECT to_timestamp(1619534123) > to_timestamp(1619530000);
  SELECT to_timestamp(1619534123) < to_timestamp(1619500000);
  

Querying using Unix Timestamps

When dealing with large amounts of time-related data, Unix Timestamps can make querying more efficient. For example, to select all records after a specific Unix Timestamp, you can simply use:

SELECT * FROM your_table WHERE timestamp_column >= to_timestamp(1619534123);

This will retrieve all records with a timestamp later than the given Unix Timestamp.

Conclusion

Unix Timestamps are widely used in programming and databases, including PostgreSQL, to represent and manipulate date/time information. In this guide, we explored how to convert Unix Timestamps to regular date/time formats and vice versa, perform calculations, and query using Unix Timestamps. Understanding how to work with Unix Timestamps in PostgreSQL can greatly enhance your ability to handle time-related data efficiently.