-- Question 1
SELECT d.*
FROM Discipline d, Epreuve e
WHERE d.code=e.discipl AND e.dateE < '2021-08-01' AND e.dateE > '2021-06-30'
GROUP BY d.code
HAVING count(*) >=ALL (SELECT count(*)
FROM Epreuve
WHERE dateE >= '2021-08-01' AND dateE <= '2021-08-31' AND d.code=discipl);

-- code |          nom          
-- ------+-----------------------
--  FEN  | Fencing
--  JUD  | Judo
--  TKW  | Taekwondo
--  GTR  | Trampoline Gymnastics
--  TRI  | Triathlon
--  TTE  | Table Tennis
--  CRD  | Cycling Road
--  SKB  | Skateboarding
--  SWM  | Swimming
--  BK3  | 3x3 Basketball
--  SRF  | Surfing
--  ROW  | Rowing
--  RUG  | Rugby Sevens
--  BSB  | Baseball/Softball
--  DIV  | Diving
--  SHO  | Shooting
--  BMX  | Cycling BMX Racing
--  CSL  | Canoe Slalom
--  ARC  | Archery
--  TEN  | Tennis
--  WLF  | Weightlifting

-- Question 2
SELECT p.nom 
FROM pays p, Athlete a, Resultat r
WHERE 

-- Question 3
SELECT 