Hi Rongrong,
The event is really happens in Tuesday, January 22, 2019 9:03:02.001
PM, so I think the first function returns 1548162182001 is correct. It is the
Unix epoch time when the event happens.
But why the timestamp passed into the from_unixtime is changed to
1548190982001? If it is not changed, I can still format 1548162182001 then pass
a time zone to get the actual date.
Timestamp is a time-zone independent value, it should not be changed, I
think.
Best
Henry
> 在 2019年1月26日，下午1:21，Rong Rong <walter...@gmail.com> 写道：
>
> Hi Henry,
>
> Unix epoch time values are always under GMT timezone, for example:
> - 1548162182001 <=> GMT: Tuesday, January 22, 2019 1:03:02.001 PM, or CST:
> Tuesday, January 22, 2019 9:03:02.001 PM.
> - 1548190982001 <=> GMT: Tuesday, January 22, 2019 9:03:02.001 PM, or CST:
> Wednesday, January 23, 2019 4:03:02.001 AM.
>
> several things are needed here
> 1. your "unix_timestamp" UDF should return actual Unix epoch time [1].
> 2. as Bowen mentioned, you will have to pass in the desired timezone as
> argument to your "from_unixtime" UDF.
>
> --
> Rong
>
> [1]: https://en.wikipedia.org/wiki/Unix_time
> <https://en.wikipedia.org/wiki/Unix_time>
> On Thu, Jan 24, 2019 at 4:43 PM Bowen Li <bowenl...@gmail.com
> <mailto:bowenl...@gmail.com>> wrote:
> Hi,
>
> Did you consider timezone in conversion in your UDF?
>
>
> On Tue, Jan 22, 2019 at 5:29 AM 徐涛 <happydexu...@gmail.com
> <mailto:happydexu...@gmail.com>> wrote:
> Hi Experts,
> I have the following two UDFs,
> unix_timestamp: transform from string to Timestamp, with the
> arguments (value:String, format:String), return Timestamp
> from_unixtime: transform from Timestamp to String, with the
> arguments (ts:Long, format:String), return String
>
>
> select
> number,
> ts,
> from_unixtime(unix_timestamp(LAST_UPDATE_TIME, 'EEE MMM dd HH:mm:Ss
> z yyyy'),'yyyy-MM-dd') as dt
> from
> test;
>
> when the LAST_UPDATE_TIME value is "Tue Jan 22 21:03:12 CST 2019”, the
> unix_timestamp return a Timestamp with value 1548162182001.
> but when from_unixtime is invoked, the timestamp with value
> 1548190982001 is passed in, there are 8 hours shift between them.
> May I know why there are 8 hours shift between them, and how can I get
> the timestamp that are passed out originally from the first UDF without
> changing the code?
>
> Thanks very much.
>
> Best
> Henry
