[GitHub] [arrow-rs] tustvold commented on issue #1936: Cast Kernel Ignores Timezone

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tustvold commented on issue #1936:
URL: https://github.com/apache/arrow-rs/issues/1936#issuecomment-1309670226

   > what's expected behavior for casting timestamp with timezone to timestamp without time zone?
   
   The specification states
   
   > /// However, if a Timestamp column has no timezone value, changing it to a
   > /// non-empty value requires to think about the desired semantics.
   > /// One possibility is to assume that the original timestamp values are
   > /// relative to the epoch of the timezone being set; timestamp values should
   > /// then adjusted to the Unix epoch (for example, changing the timezone from
   > /// empty to "Europe/Paris" would require converting the timestamp values
   > /// from "Europe/Paris" to "UTC", which seems counter-intuitive but is
   > /// nevertheless correct).
   
   As stated above, given this is the only possibility enumerated I think we should follow this. The inverse operation, i.e. removing a timezone, I would therefore expect to do the reverse i.e. `1970-01-01 01:00:01 +01:00` would become `1970-01-01 01:00:01`. This is consistent with both postgres and chrono.
   


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