BD

SELECT cod_materie, COUNT(Fisa_note.Nota)  * 100.0 / (SELECT COUNT(Persoana.cod_student)
                                                          FROM Persoana) AS Procentaj_studenti_picati
FROM Fisa_note
WHERE EXISTS (SELECT cod_materie
                  FROM Discipline
                    WHERE Fisa_note.Cod_materie = Discipline.Cod_materie AND Fisa_note.Nota < 5
                 )    GROUP BY cod_materie


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SELECT data_notare ,denumire,  COUNT(FIsa_note.cod_student) AS studenti_promovati , credite
FROM fIsa_note, discipline
WHERE Nota > 5 AND Fisa_note.cod_materie = Discipline.cod_materie
GROUP BY data_notare , denumire,  credite
ORDER BY credite DESC