1.
SELECT CONCAT(s.`id-student`," ", s.imie," ", s.nazwisko) AS "Dane studenta" ,p.`nazwa-p`, e.`data` FROM studenci s
LEFT JOIN egzaminy e ON e.`id-student`=s.`id-student`
RIGHT JOIN przedmioty p ON e.`id-przedmiot`=p.`id-przedmiot`
ORDER BY s.nazwisko, s.imie
2.
SELECT w.nazwisko, w.imie, s.nazwisko, s.imie, e.data FROM egzaminy e
JOIN wykladowcy w ON `w`.`id-wykladowcy`=`e`.`id-wykladowca`
JOIN studenci s ON s.`id-student`=e.`id-student`
JOIN osrodki o ON o.`id-osrodek`=e.`id-osrodek`
WHERE e.zdal="N"AND o.`nazwa-o` LIKE "Instytut Informatyki PL"
AND e.data=
(SELECT e.data FROM egzaminy e JOIN osrodki o ON e.`id-osrodek`=o.`id-osrodek` WHERE o.`nazwa-o` LIKE "Instytut Informatyki PL"
ORDER BY e.data ASC LIMIT 1)
ORDER BY w.nazwisko, w.imie
3.
SELECT DISTINCT s.`id-student`, s.imie, s.nazwisko FROM studenci s
LEFT JOIN (SELECT `id-student` FROM egzaminy JOIN przedmioty ON egzaminy.`id-przedmiot`=`przedmioty`.`id-przedmiot` WHERE przedmioty.`nazwa-p`LIKE "Bazy danych") e ON e.`id-student`=s.`id-student`
WHERE e.`id-student` IS NULL
4.
SELECT s.`id-student`, s.imie,s.nazwisko, p.`nazwa-p` FROM egzaminy e
JOIN studenci s ON s.`id-student`=e.`id-student`
JOIN przedmioty p ON `p`.`id-przedmiot`=`e`.`id-przedmiot`
WHERE e.zdal="N"
ORDER BY s.nazwisko
5.
SELECT w.nazwisko, w.imie, COUNT(DISTINCT e.`id-przedmiot`) AS "Liczba ró¿nych przedmiotów" FROM egzaminy e
JOIN wykladowcy w ON `w`.`id-wykladowcy`=`e`.`id-wykladowca`
GROUP BY e.`id-wykladowca`
HAVING COUNT(DISTINCT e.`id-przedmiot`)>3
6.
SELECT p.`id-przedmiot`, p.`nazwa-p`, COUNT(e.`id-student`) AS "Liczba studentów, którzy zdali" FROM egzaminy e
JOIN przedmioty p ON `p`.`id-przedmiot`=`e`.`id-przedmiot`
WHERE e.zdal="Y"
GROUP BY e.`id-przedmiot`
HAVING COUNT(e.`id-student`)=(
SELECT COUNT(e.`id-student`) FROM egzaminy e GROUP BY e.`id-student` ORDER BY 1 DESC LIMIT 1)
ORDER BY p.`nazwa-p`
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