如何在 Teradata 中将纪元时间转换为人类可读

Question

在我的 Teradata table 中，我在列 dhTimestamp

下有纪元时间戳

dhTimestamp  
1435308067705  
1434965874565  
1434763800794  
1434775876034  
1434765207057

如何在 Teradata 上将纪元时间戳转换为人类 Date/Time 格式？

Answer 1

这是标准 unixtime 的 SQL UDF：

/**********
Converting Unix/POSIX time to a Timestamp 

Unix time: Number of seconds since 1970-01-01 00:00:00 UTC not counting leap seconds (currently 24 in 2011)

Also working for negative numbers.
The maximum range of Timestamps is based on the range of INTEGERs:
1901-12-13 20:45:52 (-2147483648) to 2038-01-19 03:14:07 (2147483647)

Can be changed to use BIGINT instead of INTEGER

20101211 initial version - Dieter Noeth
**********/

REPLACE FUNCTION Epoch2Timestamp (UnixTime INT)
RETURNS TimeStamp(0)
LANGUAGE SQL
CONTAINS SQL
DETERMINISTIC
RETURNS NULL ON NULL INPUT
SQL SECURITY DEFINER
COLLATION INVOKER
INLINE TYPE 1
RETURN 
CAST(DATE '1970-01-01' + (UnixTime / 86400) AS TIMESTAMP(0))
+ ((UnixTime MOD 86400) * INTERVAL '00:00:01' HOUR TO SECOND)
;

SELECT
   Epoch2Timestamp(-2147483648)
  ,Epoch2Timestamp(0)
  ,Epoch2Timestamp(2147483647)
;

但是您的值似乎包括毫秒，这需要修改计算：

CAST(DATE '1970-01-01' + (UnixTime / 86400000) AS TIMESTAMP(3))
+ ((UnixTime / 1000.000 MOD 86400) * INTERVAL '00:00:01' HOUR TO SECOND)

编辑 2016-07-01：

夏令时存在问题（请参阅 DevEx 上 Teradata 的 this thread），这应该可以解决问题：

-- Unix time to Timestamp WITH TIME ZONE (+00:00)
REPLACE FUNCTION UnixTime_to_TimeStamp_TZ (UnixTime INT)
RETURNS TIMESTAMP(0) WITH TIME ZONE
LANGUAGE SQL
CONTAINS SQL
DETERMINISTIC
SQL SECURITY DEFINER
COLLATION INVOKER
INLINE TYPE 1
RETURN
  ((CAST(DATE '1970-01-01' + (UnixTime / 86400) AS TIMESTAMP(0) AT 0)) AT 0)
+ ((UnixTime MOD 86400) * INTERVAL '00:00:01' HOUR TO SECOND);

-- Unixtime to Timestamp, implicit TIME ZONE of the local session
REPLACE FUNCTION UnixTime_to_TimeStamp (UnixTime INT)
RETURNS TIMESTAMP(0)
LANGUAGE SQL
CONTAINS SQL
DETERMINISTIC
SQL SECURITY DEFINER
COLLATION INVOKER
INLINE TYPE 1
RETURN
  CAST(((CAST(DATE '1970-01-01' + (UnixTime / 86400) AS TIMESTAMP(0) AT 0)) AT 0)
     + ((UnixTime MOD 86400) * INTERVAL '00:00:01' HOUR TO SECOND) AS TIMESTAMP(0));

Answer 2

我能够使用以下查询将纪元列转换为时间戳..

SELECT CAST((date '1970-01-01' + CAST(epochtimecolumn/1000 AS INTEGER)/86400) AS TIMESTAMP(6)) + (CAST(epochtimecolumn/1000 AS INTEGER) MOD 86400) * INTERVAL '00:00:01' HOUR TO SECOND + (epcho_time_column_with_milliseconds MOD 1000) * INTERVAL '00:00:00.001' HOUR TO SECOND from table_name

只需将上述查询中的 epochtimecolumn 替换为您在 teradata 中运行的列。

希望对您有所帮助！！

Answer 3

这是将 EPOCH 转换为 TERADATA LOCAL 的最简单方法。

SELECT
   dhTimestamp as unix_epoc_time   , 

   to_timestamp(unix_epoc_time) utc,   

   cast(cast(utc as char(19))||'+00:00' as timestamp(0) with time zone) AT LOCAL

如果你有超过 10 位的 epoch，那么把第 10 位后的数字切掉，这样就可以了。
记住，Unix 时间是 UTC。
您的系统会将此 utc 视为本地。因此，让我们通过添加 '+00:00' 来理解它是 UTC，然后使用 AT LOCAL 或使用 "America Central" ， "America Eastern" ， "America Mountain" 等..

如何在 Teradata 中将纪元时间转换为人类可读

How to convert epoch time to Human readable in Teradata

teradata

epoch

编辑 2016-07-01：