As data analytics continues to evolve and become more global, handling timezones correctly has become an essential aspect. In Hive, one of the ways we handle timestamps in a universal format is with the UTCTIMESTAMP function.
What is Hive’s UTCTIMESTAMP?
Hive’s UTCTIMESTAMP is a function that returns the current UTC timestamp as a value in STRING format. The Universal Time Coordinated (UTC) is the time standard commonly used across the world. The UTC timestamp returned by this function is always in the ‘yyyy-MM-dd HH:mm:ss’ format.
SELECT UTCTIMESTAMP();
The above query will return a result similar to this:
2023-08-01 00:00:00
When and Why to Use Hive’s UTCTIMESTAMP?
Whenever you need a standardized timestamp that isn’t affected by the system’s local timezone or daylight saving times, UTCTIMESTAMP is the function to use. The UTCTIMESTAMP function can be used for:
- Comparing and processing data across different time zones
- Creating a universal timestamp when data is generated, for logging or tracking purposes
- As a default timestamp when none is provided during data insertion
Conversions in UTCTIMESTAMP
You can use Hive’s date functions to convert UTCTIMESTAMP into other formats or extract specific components. Here are some examples:
SELECT YEAR(UTCTIMESTAMP());
SELECT MONTH(UTCTIMESTAMP());
SELECT DAY(UTCTIMESTAMP());
SELECT HOUR(UTCTIMESTAMP());
SELECT MINUTE(UTCTIMESTAMP());
SELECT SECOND(UTCTIMESTAMP());
Each of the above queries will return the respective component of the UTCTIMESTAMP.
If you need to convert a UTCTIMESTAMP to a different timezone, you can use the from_utc_timestamp function. For example:
SELECT from_utc_timestamp(UTCTIMESTAMP(), 'PST');
Creating a Table and Inserting UTCTIMESTAMP
Here’s an example of creating a new Hive table with a timestamp column and inserting the current UTC timestamp into it:
CREATE TABLE orders (
order_id INT,
product_id INT,
timestamp STRING
);
To insert a new row with a UTC timestamp:
INSERT INTO orders (order_id, product_id, timestamp)
VALUES (1, 101, UTCTIMESTAMP());
UTCTIMESTAMP() returns a string. If you want to convert it back to a timestamp, you can use the from_utc_timestamp function. Be mindful of the timezone used in the from_utc_timestamp function to ensure correct conversions.
SELECT from_utc_timestamp(timestamp, 'UTC')
FROM orders
WHERE order_id = 1;
Hive important pages to refer
