Query to fetch functional currency of an Operating unit

SELECT
  gs.currency_code
FROM  
  gl_sets_of_books gs,
  ozf_sys_parameters_all os,
  hr_operating_units ho
WHERE 
  os.set_of_books_id = gs.set_of_books_id
  AND ho.name = ''
  AND ho.organization_id = os.org_id;

--Example
SELECT
  gs.currency_code
FROM  
  gl_sets_of_books gs,
  ozf_sys_parameters_all os,
  hr_operating_units ho
WHERE 
  os.set_of_books_id = gs.set_of_books_id
  AND ho.name = 'Vision Operations'
  AND ho.organization_id = os.org_id;