Get a fixed value on a select
If the value is always going to be the same you can do something like this:

SELECT 'USD' AS `MONEY`, a.*
  FROM INFORMATION_SCHEMA.SCHEMATA AS a


Just replace a.* with the columns you want to return and INFORMATION_SCHEMA.SCHEMATA with the schema and table(s) you want to query. 

I hope this is helpful to you.