Напредни извештаи од базата (SQL и складирани процедури)

Извештај за секој салон со бројот на вработени, термини,резервации

SELECT DISTINCT 
    fc.id AS fitnes_centar_id, 
    br_instruktori.broj_instruktori,
    br_termini.broj_termini,
    br_rezervacii.broj_rezervacii
FROM Fitnes_Centar AS fc 

LEFT JOIN (
    SELECT id_gym, COUNT(user_id_instruktor) AS broj_instruktori
    FROM Fitnes_Instruktor
    GROUP BY id_gym
) AS br_instruktori ON fc.id = br_instruktori.id_gym

LEFT JOIN (
    SELECT fi.id_gym, COUNT(t.termin_id) AS broj_termini
    FROM Fitnes_Instruktor AS fi
    JOIN Termin AS t ON fi.user_id_instruktor = t.instruktor_id
    GROUP BY fi.id_gym
) AS br_termini ON fc.id = br_termini.id_gym

LEFT JOIN (
    SELECT fi.id_gym, COUNT(r.rez_id) AS broj_rezervacii
    FROM Fitnes_Instruktor AS fi
    JOIN Termin AS t ON fi.user_id_instruktor = t.instruktor_id
    JOIN Rezervacija AS r ON t.termin_id = r.termin_id
    GROUP BY fi.id_gym
) AS br_rezervacii ON fc.id = br_rezervacii.id_gym;