■Sample401
SELECT * FROM resource ORDER BY price ASC;

■Sample402
SELECT * FROM resource ORDER BY price;

■Sample403
SELECT * FROM resource ORDER BY price DESC;

■Sample404
SELECT * FROM resource ORDER BY class;

■Sample405
SELECT * FROM resource ORDER BY class, price DESC;

■Sample406
SELECT class FROM resource;

■Sample407
SELECT class FROM resource GROUP BY class;

■Sample408
SELECT DISTINCT class FROM resource;

■Sample409
SELECT AVG(price) FROM resource;

■Sample410
SELECT class, AVG(price) FROM resource GROUP BY class;

■Sample411
SELECT * FROM score;

■Sample412
SELECT
  MAX(math) AS '数学の最高点',
  MIN(math) AS '数学の最低点',
  AVG(math) AS '数学の平均点'
FROM score;

■Sample413
SELECT
  SUM(math) AS '数学の合計',
  SUM(english) AS '英語の合計',
  SUM(science) AS '理科の合計'
FROM score;

■Sample414
SELECT COUNT(*) AS 'データの数' FROM score;

■Sample415
SELECT
  id AS '学生番号',
  math AS '数学',
  english AS '英語',
  science AS '理科',
  math + english + science AS '合計点数',
  (math + english + science) / 3.0 AS '平均点'
FROM score;

■Sample416
SELECT class, AVG(price) FROM resource
GROUP BY class HAVING COUNT(class) >= 2;

■Sample417
SELECT * FROM class_name;

■Sample418
SELECT * FROM resource
INNER JOIN class_name ON resource.class = class_name.class;

■Sample419
SELECT * FROM resource INNER JOIN class_name USING (class);

■Sample420
SELECT
  code,
  resource.name,
  price,
  class_name.name
FROM resource
INNER JOIN class_name USING (class);

■Sample421
SELECT
  code,
  resource.name,
  price,
  class_name.name
FROM resource
INNER JOIN class_name USING (class)
WHERE price >= 3000;

■Sample422
SELECT
  code,
  resource.name,
  price,
  class_name.name
FROM resource
INNER JOIN class_name USING (class)
WHERE resource.name
LIKE '%英語%'
ORDER BY price DESC;

■Sample423
SELECT
  class_name.name AS 'カテゴリ名',
  MIN(price) AS '最低価格',
  MAX(price) AS '最高価格'
FROM resource
INNER JOIN class_name USING (class)
GROUP BY class_name.name;

■Sample424
SELECT
  class_name.name AS 'カテゴリ名',
  MIN(price) AS '最低価格',
  MAX(price) AS '最高価格'
FROM resource
INNER JOIN class_name USING (class)
GROUP BY class_name.name
HAVING COUNT(class_name.name) >= 2;

■Sample425
SELECT * FROM resource CROSS JOIN class_name;

■Sample426
SELECT * FROM resource
CROSS JOIN class_name
WHERE resource.class = class_name.class;



■例題4-1
SELECT
  id AS '学生番号',
  grade AS '学年',
  name AS '名前'
FROM student ORDER BY grade DESC;


■例題4-2
SELECT
  class AS 'カテゴリ',
  MIN(price) AS '最安値',
  MAX(price) AS '最高値'
FROM resource
GROUP BY class
HAVING COUNT(class) >= 2;


■例題4-3
（1）
SELECT * FROM student INNER JOIN score ON student.id = score.id;

（2）
SELECT * FROM student INNER JOIN score USING (id);

（3）
SELECT
  student.id AS '学生番号',
  name AS '名前',
  grade AS '学年',
  math AS '数学',
  english AS '英語',
  science AS '理科'
FROM student INNER JOIN score USING(id);
