SQL - с чем его едят

Прошу помочь не могу разобраться с заданием) в друг мне тут помогут

"Дать содержательную интерпретацию результатам выполнения SQL-запросов. "

3.SELECT au_lname, au_fname
FROM authors

15.SELECT type, title_id, price
FROM titles
WHERE price*ytd_sales < advance

27.SELECT au_lname 'Фамилия', au_fname 'Имя'
FROM authors
WHERE contract=1 AND phone LIKE '408____-__2_'

39.SELECT type, MIN(pubdate), MAX(pubdate)
FROM titles
GROUP BY type

51.SELECT DISTINCT au_lname, au_fname
FROM authors a JOIN titleauthor ta ON a.au_id=ta.au_id
JOIN titles t ON ta.title_id=t.title_id
JOIN publishers p ON p.pub_id=t.pub_id
WHERE p.state= 'CA'
ORDER BY au_lname, au_fname

61.SELECT title, COUNT(DISTINCT a.au_id)
FROM titles t JOIN titleauthor ta ON t.title_id=ta.title_id
JOIN authors a ON ta.au_id=a.au_id
JOIN publishers p ON p.pub_id=t.pub_id
GROUP BY title

64.SELECT pub_name
FROM publishers
WHERE pub_id IN
(SELECT pub_id
FROM titles
WHERE type= 'business')

90.SELECT state
FROM publishers p1
GROUP BY state
HAVING COUNT(DISTINCT pub_name)=
(SELECT COUNT(*)
FROM publishers p2
WHERE EXISTS
( SELECT *
FROM titles t
WHERE p2.pub_id=t.pub_id)
AND $22.5>ALL
(SELECT price
FROM titles t
WHERE p2.pub_id=t.pub_id AND price IS NOT NULL)
GROUP BY state
HAVING p1.state=p2.state)