SELEZIONA righe con conteggio minimo (*)

Prova a utilizzare questo script come modello -

-- find minimum count
SELECT MIN(cnt) INTO @min FROM (SELECT COUNT(*) cnt FROM voting GROUP BY candidate) t;

-- show records with minimum count
SELECT * FROM voting t1
  JOIN (SELECT id FROM voting GROUP BY candidate HAVING COUNT(*) = @min) t2
    ON t1.candidate = t2.candidate;