How to Convert UTC to Local Time Zone in Redshift

When working with data in Amazon Redshift, you might often encounter timestamps stored in UTC (Coordinated Universal Time). However, for business logic, user interaction, and reports, you often need to convert these timestamps into a local time zone. This tutorial will guide you through the process of converting UTC timestamps to your local time zone using simple SQL queries in Redshift.

Step 1: Understand Time Zones in Redshift

Redshift doesn't store time zone information with the timestamp data type. The system operates using UTC timestamps, meaning that the time stored does not account for any specific time zone. To handle different time zones, you can either convert the UTC timestamp when querying the data or store the time zone information separately.

Step 2: Convert UTC to Local Time Zone Using Redshift SQL

To convert UTC to a local time zone in Redshift, you can use the CONVERT_TIMEZONE function. This function allows you to specify the source time zone (UTC) and the target time zone (your local time zone).

SELECT CONVERT_TIMEZONE('UTC', 'America/New_York', timestamp_column) 
FROM your_table;

In this example, the CONVERT_TIMEZONE function converts a timestamp from UTC to Eastern Time (America/New_York). You can replace America/New_York with any valid IANA time zone identifier (like Europe/London, Asia/Kolkata, etc.) depending on your needs.

Step 3: Time Zone List

If you are unsure of the valid time zone identifiers, you can reference the official list from the IANA Time Zone Database. Some common time zones include:

• America/New_York
• Europe/London
• Asia/Kolkata
• Australia/Sydney

Step 4: Handling Daylight Saving Time (DST)

Redshift automatically adjusts for Daylight Saving Time (DST) when using valid time zone names. For example, the time zone America/New_York will correctly adjust between Eastern Standard Time (EST) and Eastern Daylight Time (EDT) depending on the time of year.

Conclusion

By using the CONVERT_TIMEZONE function in Amazon Redshift, you can easily convert UTC timestamps into your local time zone for reporting, analytics, and user-specific data. Remember to use valid IANA time zone names and ensure proper handling of DST for accurate time conversions.