SQL justification

/* Ceci ... [586 lignes] */
SELECT C.award_cat_id, T.award_type_id
FROM Award_categories AS C, Award_types AS T
WHERE C.award_cat_typeid = T.award_type_id;

/* ... donne presque le même résultat que cela. [589 lignes] */
SELECT DISTINCT C.award_cat_id, T.award_type_id
FROM Awards AS A, Award_categories AS C, Award_types AS T
WHERE A.award_typeid = T.award_type_id AND A.award_catid = C.award_cat_id;

/* Je suppose que le premier est sous-ensemble du deuxième */