Influxdb: [Feature Request] Add "CASE WHEN"/value decoding functionality

[adigerber]

Feature Request

__Proposal:__ Add CASE WHEN to the query language. For example, when monitoring the status of a service, I track status codes. I'd like to be able to query a translation for the status codes. So if I have a svchealth measurement which contains the svcid tag and the statuscode value, I'd be able to do query the translation of statuscode this way:

select 
  svcid, 
  statuscode, 
  case 
    when statuscode = 1 then 'running'
    when statuscode = 2 then 'paused'
    when statuscode = 3 then 'stopped'
    else 'unknown'
  end as statustext
from svchealth

Or a simpler variant - a decode function which would work similarly:

select
  svcid,
  statuscode,
  decode(statuscode,
    1, 'running',
    2, 'paused',
    3, 'stopped',
    'unknown') as statustext
from svchealth

__Current behavior:__ The feature does not exist, and I have to store statustext alongside statuscode which leads to denormalization

__Desired behavior:__ The ability to decode values

__Use case:__ Show meaningful text in visualization tools

[leandro-ss]

+1

[cpatscheider]

+1

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale[bot]]

This issue has been automatically closed because it has not had recent activity. Please reopen if this issue is still important to you. Thank you for your contributions.

[natejgardner]

Please re-open, this feature is really important. _Lots_ of data, especially IIOT data, has enumerations that are ideally mapped at query time.