How to extract number of days from enum format (0 years 0 mons 0 days 0 hours 0 mins 0 secs)

I have colomn [Delay] that contains data with "enum" format like 0 years 0 mons 4 days 6 hours 0 mins 0 secs.
I need to make new colomn that only shows amount of duration in days like "4 days" or "4.25 days" will be ok.

I tried Regexextract :
regexextract([Delay], "day")
but the result
ERROR: function pg_catalog.substring(interval, character varying) does not exist Hint: No function matches the given name and argument types. You might need to add explicit type casts

What is the correct syntax for this?

Thank you

Hi @taufik
That's not "enum", it's "interval", which Metabase currently doesn't handle fully:
There's support coming for extracting period differences:

Use SQL until then.