Coming Soon: Addressing timezone inconsistency

🚨 Default behavior change coming next week 🚨

We have recently discovered that when executing queries, there are some cases where our DATETIME columns contain timezone information, and other cases where they do not. This is primarily an issue that arises with columns containing date/time information in uploaded files (we do not see this with live tables). We have decided to address this inconsistency. Starting next week, query result columns of type DATETIME will no longer contain timezone information, while columns of type DATETIMESTAMP will always contain timezone information.

The impact of this change shouldn’t be significant, and most users will see no change. However, if you have queries across ingested data which aggregate on DATETIME columns, or do DATE_ADD() style calculations, you may notice differences in your results depending on your current timezone.

If you are impacted by this change, here are some ways to clarify your intent w.r.t. timezones:

  1. CAST the resulting column to a DATETIMESTAMP to force timezones, or DATETIME to strip timezones (documentation)
  2. Use AT_TIME_ZONE() to explicitly state your timezone (documentation)
  3. Ensure that the table column type is set to be of type DATETIMESTAMP or DATETIME (documentation)

Note: If timezone information is desired, but not defined, UTC is assumed. 

Please contact with any questions or concerns. As always, we’re happy to help.