Can You Use a Column for the Timezone Parameter of at Time Zone in Presto/Athena

Can you use a column for the timezone parameter of AT TIME ZONE in Presto / Athena?

It indeed looks like a bug in the engine. What is interesting however is, that the underlying function works with a column parameter. So you can use this as a workaround.

SELECT at_timezone(date_utc,x.timezone)
FROM
(
  SELECT
    TIMESTAMP '2018-09-09 12:00:00' as date_utc,
    'America/Chicago' as timezone

) x;

Presto SQL : Changing time zones using time zone string coming as a result of a query is not working

AT TIME ZONE accepts only literal or interval.

Presto 320 adds with_timezone (for timestamp values) at_timezone (for timestamp with time zone values) exactly for this purpose.

If you are using older Presto version (such as Athena as of this writing), you can use following workaround. You can cast your timestamp value to a varchar, concatenate with zone and cast to timestamp with time zone.

presto> select cast(cast(t as varchar) || ' ' || zone as timestamp with time zone)
  from (values (timestamp '2017-06-01 12:34:56.789', 'US/Pacific')) x(t, zone);
                    _col0
---------------------------------------------
 2017-06-01 12:34:56.789 America/Los_Angeles
(1 row)

(Note: tested on Presto 320. If this doesn't work on Athena yet, let me know.)

Presto: Publish a table with timezone altered to the correct zone

SELECT CAST(SUBSTR(CAST((FROM_UNIXTIME(CAST(1578514469000 AS BIGINT)/1000) AT TIME ZONE 'US/Pacific') AS varchar), 1, 23) AS timestamp)

converting to timestamp with time zone failed on Athena

Short summary:

SELECT CAST(From_iso8601_timestamp('2018-01-01T15:00:00Z') AS timestamp) as "real_date"

Full story:

Unfortunately Athena doesn't fully support all Presto features, it has limitations and is technically a few versions behind Presto. There's some attempt to make Athena integrate closely with the AWS Glue Metastore, which while based on Hive's metastore has some inconsistencies. I wish that Spark, Hive, Glue, Athena, Presto et al would just work with the same metastore, it would make life easier, but back to your issue:

This document about an older teradata fork of Presto mentions some issues with timestamp in presto:

Presto’s method for declaring timestamps with/with out timezone is not
sql standard. In Presto, both are declared using the word TIMESTAMP,
e.g. TIMESTAMP '2003-12-10 10:32:02.1212' or TIMESTAMP '2003-12-10
10:32:02.1212 UTC'. The timestamp is determined to be with or without
timezone depending on whether you include a time zone at the end of
the timestamp. In other systems, timestamps are explicitly declared as
TIMESTAMP WITH TIME ZONE or TIMESTAMP WITHOUT TIME ZONE

The version of Presto that Athena is forked from does support both timestamp and timestamp with timezone but with that quirk as mentioned in the teradata docs which shouldn't be an issue. The real issue is that Athena does not support timestamp with timezone.

The presto docs you've linked to show that the function returns a value of that unsupported type timestamp with timezone, so you need to cast it as something else that is supported. It's an oversight that Athena allows functions and casting to a datatype that is then not supported, and hopefully that will be remedied, but for now you have to work around it.

What you need to do is use the CAST() function around that function call, which will change the type from timestamp with time zone into timestamp

Unfortunately you probably can't cast the string directly to a timestamp, although it depends on how the string is formatted. You also can't use the style of casting where you write timestamp before the string e.g. can't do timestamp '2018-01-01 15:00:00' for reasons I will explain below.

Type returned by the from_iso1601_timestamp() function

SELECT typeof("real_date") AS real_date_type
FROM
(
SELECT From_iso8601_timestamp('2018-01-01T15:00:00Z') as "real_date"
)

timestamp with time zone

This doesn't work

SELECT typeof("real_date") AS real_date_type
FROM
(
SELECT CAST('2018-01-01T15:00:00Z' AS timestamp) as "real_date"
)

SQL Error [FAILED]: INVALID_CAST_ARGUMENT: Value cannot be cast to
timestamp

This style of Casting also returns timestamp with timezone :(

Note that the SELECT part of this works, and it says that it is a timestamp, but for some internal inconsistency reason you can't create a view and you'll get an error.

CREATE OR replace VIEW test 
AS 
SELECT typeof( "real_date" ) AS real_date_type
FROM
(
SELECT  timestamp '2018-01-01 15:00:00' as "real_date"
)

SQL Error [FAILED]: Could not initialize class
com.facebook.presto.util.DateTimeZoneIndex

For whatever reason, creating a view requires that java class while parsing the value in the select doesn't. It's a bug that should be addressed.

This works yay

CREATE OR REPLACE VIEW test
AS
SELECT typeof("real_date") AS real_date_type
FROM
(
SELECT CAST(From_iso8601_timestamp('2018-01-01T15:00:00Z') AS timestamp) as "real_date"
)

How do I convert time zones in AWS Athena

Ahtena supports at_timezone function:

WITH dataset (t, tz) AS (
    VALUES (TIMESTAMP '2001-08-22 03:04:05.321 America/Los_Angeles', 'America/New_York')
)

select at_timezone(t, tz)
FROM dataset

Output:

---