Pour mémoire, je suis d'accord avec le commentaire de @DamienBlack, cependant si il fallait le faire en une seule requête a UNION ALL
pourrait faire l'affaire :
(
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;
)