BigQuery 将 unix 时间戳结构转换为日期时间结构

Question

I have a BigQuery table that contains a struct column called daySliderTimes in the following form:

daySliderTimes STRUCT<_field_1 STRUCT<_seconds INT, _nanoseconds INT>, _field_1 STRUCT<_seconds INT, _nanoseconds INT> .

_field_1 and _field_2 represent two different timestamps. _seconds and _nanoseconds represent time since the unix epoch.

I want to convert the data into a new STRUCT with the following form:

daySlidertimes STRUCT<startTime DATETIME, endTime DATETIME>

This is the table as seen in the BigQuery UI:

Answer 1

If you want to create a new table from the old one with the format daySlidertimes STRUCT<startTime DATETIME, endTime DATETIME> , you can cast the data in milliseconds and so then transform it to TIMESTAMP with the function "TIMESTAMP_MICROS", check this link to see the amount of functions to parse timestamp [1].

An example of the query should look something like this:

CREATE TABLE `project.dataset.new_table` AS 
   SELECT searchDocId, 
   STRUCT(TIMESTAMP_MICROS(CAST( 
   ((daySliderTimes.field1.seconds * 1e+6)  + 
   ROUND(daySliderTimes.field1.nanoseconds * 0.001)) AS INT64)) as 
   startTime, 
   TIMESTAMP_MICROS(CAST( ((daySliderTimes.field2.seconds * 1e+6)  + 
   ROUND(daySliderTimes.field2.nanoseconds * 0.001)) AS INT64)) as endTime) 
   as daySliderTimes, 
   enabledDaySliders
FROM `project.dataset.old_table`

[1] https://cloud.google.com/bigquery/docs/reference/standard-sql/functions-and-operators#parse_timestamp

Answer 2

You can use TIMESTAMP_SECONDS() function. This function converts the seconds to DATETIME format.

Therefore, you are ale to transform daySliderTimes._field_1.seconds to a date using TIMESTAMP_SECONDS() function. As well as, for _field_2 , then aggregate them in a new struct format.

During the creation of the view or table, in your select you can do the following:

WITH table_newStruct as(
  SELECT 
#Select all the desired fields
         searchDocId,
         STRUCT(TIMESTAMP_SECONDS(daySliderTimes._field_1.seconds) as startTime, 
         TIMESTAMP_SECONDS(daySliderTimes._field_.seconds) as endTime) as new_daySlidertimes

FROM 'table_source')

SELECT searchDocId, new_daySlidertimes 
FROM 'table_newStruct'

In addition, the returned TIMESTAMP should be in the following format 1970-01-01 00:00:00 UTC . You can format it using the FORMAT_DATE() function.