For simplicity, assume I have a panel dataset with two firms with 10 years' revenue data (2001-2010).
For revenue, firm A has one missing value in 2002. Firm B has no missing values.

I am trying to generate dummy = 1 for all years unless a firm has missing values for all years.
Basically, I would like to have dummy = 1 for both firms for all years.

I tried the below, but it only generate dummy = 1 for non-missing values..

Code:
gen  dum = 0
bysort firmid:  replace dum= 1 if revenue !=.

With the code I have, I see dum = 0 in 2002, I need it to be dum = 1.
How could we do that?