Calculate HH:MM from decimal time within Grafana... transform, override or other?

I’m trying to display time as HH:MM in a gauge panel, and I’m not sure what options are available to me to calculate and display that format. Right now, I’m recording a value into my Influx db as nanoseconds since epoch, and I’m retrieving that value, and calculating decimal time in my query like so:

My query in Grafana is :

SELECT (((("timestamp" - "midnight" )/1000000000)/60)/60) FROM "measurement"

for values:

1604337300000000000 = "timestamp" in database: Monday, November 2, 2020 11:15:00 AM GMT-06:00
1604296800000000000 = midnight (GMT - 06:00)

my query will return 11.25. I would normally isolate the 0.25 part and then multiply that by 60 (minutes in an hour) to get to :15.

I don’t think InfluxQL can do what I want in the query (but I’m open to doing the calculation in a query).

I don’t know what options are available to me in Grafana, but it seems like transform or override might have the functionality that I need. Can anyone point me in the right direction while I’m researching?

Following up because I know there are a lot of HA people that use Grafana, and they may not know a ton of programming. The Graph panel has a “Standard Options” field on the “Field” tab. In the “Unit” there are a lot of options, scroll down to “duration (hh:mm:ss)”. I’m recording these timestamps in nSecs, and this panel was looking for seconds, so my query above was changed to:

SELECT (("timestamp" - "midnight" )/1000000000) FROM "measurement"

“Midnight” was calculated from the timestamp when I wrote the data in my CRUD operation. And this was the result: