[GitHub] rumbin opened a new issue #3704: [SQLLab] datetime columns interpreted as strings when exporting _cached_ result to CSV

[GitBox <gi...@apache.org>]

rumbin opened a new issue #3704: [SQLLab] datetime columns interpreted as strings when exporting _cached_ result to CSV
URL: https://github.com/apache/incubator-superset/issues/3704
 
 
   ### Foreword
   I reported this issue in #3695, together with a related one.
   As I found out that the two are not as closely related as I thought, I decided to split them...
   
   ### Superset version
   0.20.4
   
   ### Expected results
   Datetime columns are interpreted and formatted correcty when exporting a _cached_ query result as CSV.
   
   ### Actual results
   The datetime columns are, when fetched from the cache, interpreted as string/object. When exporting the data to CSV, any `date_format` setting in the `CSV_EXPORT` options is without effect.
   
   Even if no `date_format` is specified, the fromat of timestamps differd from the one obtained from CSV exports that are created without caching, as the default export fromat from pandas' `to_csv` method separates date and time with a space instead of a `T`. The latter is what is obtained when exporting the results from cache.
   
   One major drawback of this issue is that MS Excel cannot _automatically_ deal with ISO timestamps which feature the `T` separator between date and time. Unfortunately, I think that we have to adapt to this embarassing inability of Excel.
   
   ### Steps to reproduce
   Have a cache backend configured for superset (here: Redis) and execute and then export the following query:
   ```
   select now()::timestamp as my_timestamp
   ```
   
   

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