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 On Thu, Jan 24, 2019 at 4:43 PM Bowen Li <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> 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 >> >
