contoh_sql

SELECT
   f.namaalternatif,d.namakriteria,costbenefit,nilai,n_max,n_min, IF(d.costbenefit='benefit',c.nilai/d.n_max,d.n_min/c.nilai) AS cos_benefit
FROM
  (nilai_alternatif c
   INNER JOIN
   ( SELECT a.id_kriteria,b.namakriteria,b.costbenefit,a.n_max,a.n_min FROM
       ( SELECT
          id_kriteria, MAX(nilai) AS n_max, MIN(nilai) AS n_min
        FROM
          nilai_alternatif
        GROUP BY
          id_kriteria
       ) a
       INNER JOIN
          kriteria b
       ON a.id_kriteria = b.idkriteria
   ) d
   ON c.id_kriteria=d.id_kriteria) INNER JOIN alternatif f ON c.id_alternatif=f.idalternatif;