Nacho 004, a ver si te sirve esto:
Código sql:
Ver original(SELECT COUNT(*)totcom, 'gastronomia_comentarios' AS tabla, id_gastronomia AS ID
FROM `gastronomia_comentarios`
WHERE votado = 1 AND publicado = 1 GROUP BY id_gastronomia)
UNION ALL
(SELECT COUNT(*), 'bares_comentarios', id_bares
FROM `bares_comentarios`
WHERE votado = 1 AND publicado = 1 GROUP BY id_bares)
UNION ALL
(SELECT COUNT(*), 'boliches_comentarios', id_boliches
FROM `boliches_comentarios`
WHERE votado = 1 AND publicado = 1 GROUP BY id_boliches) ORDER BY totcom DESC, tabla