SQL 05.11.2021

SELECT MIN(placa_pod) AS "Minimalna", MAX(placa_pod) AS "Maksymalna", MAX(placa_pod)-MIN(placa_pod) AS "Roznica" FROM pracownicy;SELECT avg(placa_pod) AS "Srednia Placa" FROM pracownicy GROUP BY etat ORDER BY avg(placa_pod) DESC;
SELECT avg(placa_pod) AS "Srednia Placa" FROM pracownicy GROUP BY etat ORDER BY avg(placa_pod) DESC;
SELECT COUNT(*) FROM pracownicy WHERE etat="PROFESOR";
SELECT id_zesp, SUM(placa_pod+placa_dod) "Sumaryczna placa" FROM pracownicy GROUP BY id_zesp;
SELECT id_zesp, COUNT(*) FROM pracownicy WHERE id_zesp IS NOT NULL GROUP BY id_zesp HAVING COUNT(*)>2 ORDER BY COUNT(*);
SELECT AVG(placa_pod) AS "Srednia Placa", COUNT(*) AS "Liczba Pracownikow" FROM pracownicy WHERE YEAR(zatrudniony) <= 1990 GROUP BY etat;
SELECT id_szefa, MIN(placa_pod) FROM pracownicy WHERE id_szefa IS NOT NULL GROUP BY id_szefa;