SQL Server SWITCHOFFSET() Function

The SWITCHOFFSET() function in SQL Server is used to change the time zone offset of a datetime value and returns the new datetime. The function takes a datetime value and a time zone offset as input parameters and converts the input datetime to a datetime value in the specified time zone. The function can help users convert datetime between different time zones, and is very useful in cross-time zone applications.

Syntax

SWITCHOFFSET(datetimeoffset, time_zone)

• datetimeoffset: The datetime value to change the time zone offset.
• time_zone: The target time zone offset to convert to.

Use cases

Here are some scenarios where the SWITCHOFFSET() function is useful:

• Cross-time zone applications: In applications that span multiple time zones, this function can easily convert datetime from one time zone to another.
• Reports with multiple time zones: When generating reports containing data from different time zones, this function can be used to convert all datetime values to datetime values in the specified time zone to ensure data consistency and accuracy.
• Databases with multiple time zones: In databases with multiple time zones, this function can be used to convert all datetime values to datetime values in the specified time zone to ensure data consistency and accuracy.

Examples

Example 1

Suppose we have a table containing datetime and time zone offset, where all datetime values are based on Pacific Time.

We want to convert these datetime values to New York Time. Here is an example query using the SWITCHOFFSET() function:

SELECT SWITCHOFFSET(datetime, '-05:00') AS new_datetime
FROM table_name;

After running the above query, we will get the following result:

As we can see, using the SWITCHOFFSET() function, we successfully converted the datetime values from Pacific Time to New York Time.

Example 2

Suppose we have a table containing datetime and time zone offset, where all datetime values are based on New York Time.

We want to convert these datetime values to UTC Time. We can use the SWITCHOFFSET() function to achieve this.

SELECT CONVERT(
    datetimeoffset,
    SWITCHOFFSET(
      CONVERT(datetimeoffset, datetime, time_zone),
      '+00:00'
    )
  ) AS utc_datetime
FROM table_name;

This will return a result set containing the converted UTC Time.

In this example, we first convert the datetime and time_zone columns to the datetimeoffset type. Then, we use the SWITCHOFFSET() function to convert the datetime to UTC Time, and then convert the result back to the datetimeoffset type. Finally, we use the CONVERT() function to convert the result to the format in the utc_datetime column.

Conclusion

The SWITCHOFFSET() function is a very useful function that can convert datetime from one time zone to another or convert datetime to a time based on UTC time. Its syntax is relatively simple and easy to use. However, it should be noted that it only applies to the datetimeoffset data type and cannot be used for other types of datetime data.