Para constar, concordo com o comentário de @DamienBlack, porém se tinha que ser feito em uma consulta a
UNION ALL
poderia fazer o truque:(
SELECT VENDOR_fullname as name, SUM(POTENTIAL_RECOVERY) as recovery
FROM COMPLETE
GROUP BY VENDOR_fullname
ORDER BY SUM(POTENTIAL_RECOVERY) DESC
LIMIT 10
)
UNION ALL
(
SELECT 'All others' as name, SUM(subtotal) as recovery
FROM
(
SELECT SUM(POTENTIAL_RECOVERY)
FROM COMPLETE
GROUP BY VENDOR_fullname
ORDER BY SUM(POTENTIAL_RECOVERY) DESC
LIMIT 10, 18446744073709551615
) as subtotal;
)