使用Go从关系数据库中存储/检索大量数据

What is a proper way to represent huge numbers from database in GO?

I have a Postgres table with column of numeric type. Postgres internally represents it as varchar, allowing it to have virtually unlimited size. My values won't exceed 10 ^ 28 tough. Additionally, this column is nullable.

I know that go has big.Int for representing such numbers, but there is no nullable equivalent in sql package, sql.NullInt64 being the biggest out there.

So what is a proper way of representing such column in go?