Solving the Mystery: Extract Day/Hour/Minute/Seconds Return Different Values in Oracle and Snowflake

Are you struggling to understand why the extract function is returning different values for day, hour, minute, and seconds in Oracle and Snowflake? You’re not alone! In this article, we’ll delve into the world of date and time functions in both databases, exploring the reasons behind these inconsistencies and providing clear, actionable solutions to get you back on track.

Understanding the Extract Function

The extract function is a powerful tool used to extract specific components from a datetime or timestamp value. In both Oracle and Snowflake, the extract function is used to retrieve individual parts of a datetime value, such as day, hour, minute, or second. However, the way these databases handle datetime values and the extract function can lead to unexpected results.

Oracle’s Extract Function

In Oracle, the extract function is used with the following syntax:

EXTRACT(.component FROM datetime_value)

Where:

• component: The specific component to extract from the datetime value, such as DAY, HOUR, MINUTE, or SECOND.
• datetime_value: The datetime or timestamp value from which to extract the component.

For example:

SELECT EXTRACT(DAY FROM TIMESTAMP '2022-07-25 14:30:00') FROM dual;

This query would return the value 25, representing the day component of the datetime value.

Snowflake’s Extract Function

In Snowflake, the extract function is used with the following syntax:

EXTRACT('component' FROM datetime_value)

Where:

• component: The specific component to extract from the datetime value, such as DAY, HOUR, MINUTE, or SECOND.
• datetime_value: The datetime or timestamp value from which to extract the component.

For example:

SELECT EXTRACT('DAY' FROM TIMESTAMP '2022-07-25 14:30:00');

This query would return the value 25, representing the day component of the datetime value.

The Mystery Unfolds: Different Values in Oracle and Snowflake

So, why do the extract functions return different values in Oracle and Snowflake? The answer lies in the way each database handles datetime values and time zones.

Time Zones and Datetime Values

In Oracle, datetime values are stored in the database’s time zone, which can be set using the TZ parameter in the CREATE DATABASE statement or the ALTER SESSION statement. When you extract a component from a datetime value in Oracle, the database takes into account the time zone and adjusts the result accordingly.

In Snowflake, datetime values are stored in the UTC time zone, regardless of the account’s time zone setting. When you extract a component from a datetime value in Snowflake, the database returns the value as it would be in the UTC time zone.

Impact on Extract Function Results

Due to these differences in datetime value handling, the extract function can return different values in Oracle and Snowflake. For example:

Database	Extract Function	Result
Oracle	EXTRACT(DAY FROM TIMESTAMP ‘2022-07-25 14:30:00’)	25 (adjusted for Oracle’s time zone)
Snowflake	EXTRACT(‘DAY’ FROM TIMESTAMP ‘2022-07-25 14:30:00’)	25 (in UTC time zone)

In this example, the extract function returns different values for the day component in Oracle and Snowflake due to the different time zone handling.

Solutions to the Mystery

Now that we’ve uncovered the reasons behind the inconsistencies, let’s explore the solutions to get accurate results from the extract function in both Oracle and Snowflake.

Oracle Solutions

To get consistent results in Oracle, you can:

1. Use the FROM_TZ function to convert the datetime value to a specific time zone before extracting the component:

SELECT EXTRACT(DAY FROM FROM_TZ(TIMESTAMP '2022-07-25 14:30:00', 'UTC')) FROM dual;

2. Adjust the extracted component to account for the time zone difference:

SELECT EXTRACT(DAY FROM TIMESTAMP '2022-07-25 14:30:00') + (EXTRACT(TIMEZONE_HOUR FROM TIMESTAMP '2022-07-25 14:30:00') / 24) FROM dual;

Snowflake Solutions

To get consistent results in Snowflake, you can:

1. Use the CONVERT_TIMEZONE function to convert the datetime value to a specific time zone before extracting the component:

SELECT EXTRACT('DAY' FROM CONVERT_TIMEZONE('UTC', TIMESTAMP '2022-07-25 14:30:00'));

2. Adjust the extracted component to account for the time zone difference:

SELECT EXTRACT('DAY' FROM TIMESTAMP '2022-07-25 14:30:00') + (EXTRACT('HOUR' FROM TIMESTAMP '2022-07-25 14:30:00') / 24);

Conclusion

In this article, we’ve explored the mysteries of the extract function in Oracle and Snowflake, uncovering the reasons behind the inconsistent results. By understanding the differences in datetime value handling and time zone settings, we can adapt our queries to get accurate results from the extract function in both databases.

Remember to use the solutions outlined in this article to ensure consistent results in your Oracle and Snowflake queries. Happy querying!

This article is optimized for the keyword “extract day/hour/minute/seconds are returning different values in oracle and snowflake” and is designed to provide clear, actionable solutions to this common issue in database development.

Frequently Asked Question

Get to the bottom of the mystery surrounding extract functions in Oracle and Snowflake!