I have to write a drop down query for countries. But USA should always be first. The rest of the countries are in alphabetical order I tried the following query

SELECT      
           countries_id
        ,countries_name

        FROM get_countries
        WHERE 
             countries_id = 138
        UNION 

        SELECT 
                countries_id
              ,countries_name

         FROM get_countries 
        WHERE   
                  countries_id != 138
        ORDER BY 2 ASC