SQL Помогите пожалуйста с написанием запросов, завтра экзамен

SELECT DISTINCT C.AUTHOR
FROM CONTENTS C
INNER JOIN JOURNAL J
ON J.ISBN=C.ISBN
AND EXTRACT(MONTH FROM J.DATE)=EXTRACT(MONTH FROM ADD_MONTHS(SYSDATE, -1))

WITH MINDATES AS (
SELECT R.ID, MIN(B.YEAR) AS YEAR
FROM READERS R
INNER JOIN JOURNAL J
ON R.ID=J.READER_ID
INNER JOIN BOOKS B
ON J.ISBN=B.ISBN
WHERE B.YEAR>=1900
AND B.YEAR < 2000
GROUP BY R.ID)
SELECT R.FIRST_NAME, R.LAST_NAME, B.TITLE
FROM READERS R
INNER JOIN JOURNAL J
ON R.ID=J.READER_ID
INNER JOIN BOOKS B
ON J.ISBN=B.ISBN
INNER JOIN MINDATES M
ON B.YEAR=M.YEAR
AND B.ID=R.ID
ORDER BY 2, 1

SELECT B.NAME, B.YEAR, AVG(C.PAGES)
FROM BOOKS B
INNER JOIN CONTENTS C
ON B.ISBN=C.ISBN
WHERE B.YEAR>2015
GROUP BY B.NAME, B.YEAR
HAVING AVG(C.PAGES) < 10
ORDER BY 2, 1

SELECT DISTINCT C.NAME
FROM CONTENTS C
MINUS
SELECT C.NAME
FROM CONTENTS C
INNER JOIN JOURNAL J
ON J.ISBN=C.ISBN

SELECT DISTINCT C.AUTHOR
FROM CONTENTS C
MINUS
SELECT C.AUTHOR
FROM CONTENTS C
INNER JOIN JOURNAL J
ON J.ISBN=C.ISBN
INNER JOIN READERS R
ON J.READER_ID=R.ID
AND R.LAST_NAME||' '||R.FIRST_NAME=C.AUTHOR --Я ХЗ, как там автор записан, предполагаю, что ФАМИЛИЯ ИМЯ