SQL Query: How to improve? - mysql

Question

I have two tables in a MySQL database:
Book(title, publisher, year) title is primary key
Author(name, title) title is foreign key to Book
I am trying to select the name of the Authors that published a book each year from 2000 to 2005 inclusive. This SQL query works, but is there a way to do this that makes it easier to change the date range if needed?
SELECT DISTINCT name
FROM Author
WHERE name IN (SELECT Author.name
FROM Author INNER JOIN Book ON (Author.title = Book.title)
WHERE year = 2000)
AND name IN
(SELECT Author.name
FROM Author INNER JOIN Book ON (Author.title = Book.title)
WHERE year = 2001)
AND name IN
(SELECT Author.name
FROM Author INNER JOIN Book ON (Author.title = Book.title)
WHERE year = 2002)
AND name IN
(SELECT Author.name
FROM Author INNER JOIN Book ON (Author.title = Book.title)
WHERE year = 2003)
AND name IN
(SELECT Author.name
FROM Author INNER JOIN Book ON (Author.title = Book.title)
WHERE year = 2004)
AND name IN
(SELECT Author.name
FROM Author INNER JOIN Book ON (Author.title = Book.title)
WHERE year = 2005);

Answer 1

Here's two ways to do it, and how another approach is wrong due to a subtle fault.
SQL Fiddle
MySQL 5.5.32 Schema Setup:
create table Book (title varchar(10), year int) ;
create table Author (name varchar(10), title varchar(10));
insert Book values
('Book1',2000),('Book2',2000),
('Book3',2000),('Book4',2000),
('Book5',2000),('Book6',2000),
('Book7',2001),('Book8',2002),
('Book9',2003),('Book10',2004),
('Book11',2005);
insert into Author values
('Author1','Book1'),('Author1','Book2'),
('Author1','Book3'),('Author1','Book4'),
('Author1','Book5'),('Author1','Book6'),
('Author2','Book6'),('Author2','Book7'),
('Author2','Book8'),('Author2','Book9'),
('Author2','Book10'),('Author2','Book11');
# author1 has written 6 books in one year
# author2 has written 1 book in every of the six years
Query 1:
# incorrect as it matches author1 who has 6 books in a single year
SELECT name from Author
INNER JOIN BOOK on Author.title = Book.Title
WHERE year IN (2000,2001,2002,2003,2004,2005)
GROUP BY name
HAVING COUNT(name) = 6
Results:
| NAME |
|---------|
| Author1 |
| Author2 |
Query 2:
# correct as it counts distinct years
SELECT name from Author
INNER JOIN BOOK on Author.title = Book.Title
WHERE year IN (2000,2001,2002,2003,2004,2005)
GROUP BY name
HAVING COUNT(DISTINCT year) = 6
Results:
| NAME |
|---------|
| Author2 |
Query 3:
# correct using relational division
SELECT DISTINCT name
FROM Author A1
INNER JOIN Book B1 ON A1.title = B1.Title
WHERE NOT EXISTS (
SELECT *
FROM Book B2
WHERE year IN (2000,2001,2002,2003,2004,2005)
AND NOT EXISTS (
SELECT *
FROM Author A2
INNER JOIN Book B3 ON A2.title = B3.Title
WHERE (A1.name = A2.name)
AND (B3.year = B2.year)
)
)
Results:
| NAME |
|---------|
| Author2 |

Answer 2

I would put an 'OR' clause in the where statement. It depends on how your table is set up but it should work:
SELECT DISTINCT name
FROM Author
WHERE name IN (SELECT Author.name
FROM Author INNER JOIN Book ON (Author.title = Book.title)
WHERE year = 2000)

Answer 3

Something like this, I didn't test it but you can group by and select only the ones that would have 6 rows:
SELECT a.name FROM Author a
INNER JOIN Book b
ON a.title = b.title
WHERE b.year BETWEEN 2000 AND 2005
GROUP BY name HAVING COUNT(a.name) = 6

Answer 4

I would use arguments
declare #StartYear int = 2000
declare #EndYear int = 2005
select a.name
from author a
inner join book b on a.title = b.title
where year between #StartDate and #EndDate
group by a.name
having count(distinct year) = #EndDate- #StartDate
It's easy to modify and modify itself whenever year you input