I found a way to do it.

Please ignore or delete this post

Ok, one more question because I m getting an error ...

My field, TS_TIME_ASSIGNED is an integer

If I replace the '508621' by my field TS_TIME_ASSIGNED in the second line (SET @date...

Well, doesn't seem to work fine.

I've got an 'Arithmetic overflow error converting expression to data type datetime'

I have a value for exemple: 508621 (seconds)

I want to display: 5 days 21...

Excellent, working fine 🙂