Hi!
Yes this is supported 
There is no variable called $column, but can use $labels in custom annotations to reference some or all of the labels returned by the datasource query. You can find the docs on this here.
If you are using PostgreSQL you can do something like this:
SELECT 1, id::text, domain, chassis, model, oper_state_code FROM servers WHERE oper_state_code = 'degraded';
This is how it looks:
