How to convert a Date String from UTC to Specific TimeZone in HIVE?

问题

My Hive table has a date column with UTC date strings. I want to get all rows for a specific EST date.

I am trying to do something like the below:

Select * 
from TableName T
where TO_DATE(ConvertToESTTimeZone(T.date))  = "2014-01-12" 

I want to know if there is a function for ConvertToESTTimeZone, or how I can achieve that?

I tried the following but it doesnt work (my default timezone is CST):

TO_DATE(from_utc_timestamp(T.Date) = "2014-01-12" 
TO_DATE( from_utc_timestamp(to_utc_timestamp (unix_timestamp (T.date), 'CST'),'EST'))

Thanks in advance.

Update:

Strange behavior. When I do this:

select "2014-01-12T15:53:00.000Z", TO_DATE(FROM_UTC_TIMESTAMP(UNIX_TIMESTAMP("2014-01-12T15:53:00.000Z", "yyyy-MM-dd'T'hh:mm:ss.SSS'Z'"), 'EST')) 
from TABLE_NAME T1
limit 3

I get

    _c0                          _c1
0   2014-01-12T15:53:00.000Z    1970-01-16
1   2014-01-12T15:53:00.000Z    1970-01-16
2   2014-01-12T15:53:00.000Z    1970-01-16

回答1:

Your system timezone CST doesn't matter for converting UTC to EST in Hive. You should be able to get the correct results with:

TO_DATE(FROM_UTC_TIMESTAMP(UNIX_TIMESTAMP(T.date, "yyyy-MM-dd'T'hh:mm:ss.SSS'Z'") * 1000, 'EST'))

Note that because UNIX_TIMESTAMP returns seconds, you will lose the millisecond component of your timestamp.

回答2:

This converts to CST with the daylight savings hour shift:

to_date(FROM_UTC_TIMESTAMP(UNIX_TIMESTAMP(eff_timestamp, "yyyy-MM-dd'T'hh:mm:ss.SSS'Z'") * 1000, 'CST6CDT')) 

来源：https://stackoverflow.com/questions/28508640/how-to-convert-a-date-string-from-utc-to-specific-timezone-in-hive