SELECT t1.id, t1.job, t1.score, t1.t_rank FROM ( SELECT g.*, DENSE_RANK() OVER (PARTITION BY g.job ORDER BY g.score DESC) t_rank FROM grade g ) t1, ( SELECT g.job, FLOOR((COUNT(g.job) + 1) / 2) start, FLOOR((COUNT(g.job) + 2) / 2) end FROM grade g ...