Comma separating numbers without advance knowledge of number of digits in Postgres

Question

In Postgres 9.5:

select to_char(111, 'FM9,999'); -- gives 111
select to_char(1111, 'FM9,999'); -- gives 1,111
select to_char(11111, 'FM9,999'); -- gives #,### !!!

How can I format my numbers with commas without advance knowledge/assumption of maximum number of possible digits preferably by using built-in stuff like above?

Answer 1

Add another digit or the maximum possible value:

select to_char(11111, 'FM9,999,999');