# How to Calculate Time Difference in Amazon Athena/Presto

Amazon Athena, a serverless interactive query service, leverages Presto, an open-source distributed SQL query engine, to analyze data in Amazon S3. For data scientists and software engineers dealing with time series data, calculating time difference is a frequent requirement. This article will guide you on how to calculate time difference in seconds and minutes using Amazon Athena/Presto.

# How to Calculate Time Difference in Amazon Athena/Presto

Amazon Athena, a serverless interactive query service, leverages Presto, an open-source distributed SQL query engine, to analyze data in Amazon S3. For data scientists and software engineers dealing with time series data, calculating time difference is a frequent requirement. This article will guide you on how to calculate time difference in seconds and minutes using Amazon Athena/Presto.

## Understanding Time Functions in Presto

Presto provides a wide range of date and time functions to manipulate data. For calculating time difference, the key functions we will use are `date_diff()` and `extract()`.

## A Quick Overview of date_diff()

The `date_diff()` function in Presto returns the difference between two dates, times, or timestamps. It can be used to calculate the difference in various units like second, minute, hour, day, etc.

Here’s the syntax:

``````date_diff(unit, timestamp1, timestamp2)
``````

## Usage of extract()

The `extract()` function allows you to extract fields such as year, month, day, hour, minute, second from a date or time value.

``````extract(field FROM source)
``````

## Calculating Time Difference in Seconds or Minutes

Now, let’s dive into how to calculate time difference in seconds and minutes.

Consider a dataset with start_time and end_time column values in TIMESTAMP format. Here’s how to calculate the time difference:

``````SELECT
date_diff('second', start_time, end_time) as time_diff_seconds,
date_diff('minute', start_time, end_time) as time_diff_minutes
FROM your_table;
``````

This will calculate the time difference in seconds and minutes from the TIMESTAMP columns start_time and end_time.

However, if your time data is in other formats, you might need to first convert it to TIMESTAMP using the `from_iso8601_timestamp()` function:

``````SELECT
date_diff('second', from_iso8601_timestamp(start_time), from_iso8601_timestamp(end_time)) as time_diff_seconds,
date_diff('minute', from_iso8601_timestamp(start_time), from_iso8601_timestamp(end_time)) as time_diff_minutes
FROM your_table;
``````

In case you have DATE or TIME data and you want to calculate the difference in seconds or minutes, you can use the `extract()` function:

``````SELECT
(extract(minute FROM time_data)*60 + extract(second FROM time_data)) as time_diff_seconds,
extract(minute FROM time_data) as time_diff_minutes
FROM your_table;
``````

This will calculate the time difference in seconds and minutes from the TIME or DATE column time_data.

## Conclusion

Calculating time difference in Amazon Athena/Presto is straightforward once you understand the key functions like `date_diff()` and `extract()`. These functions are powerful tools for manipulating and analyzing time series data in Amazon Athena/Presto.

Remember, understanding your data and its format is crucial when dealing with time calculations. Always ensure that your time data is in the correct format before attempting to calculate time difference.

Stay tuned for more practical guides and tips on data science and software engineering!