mysql使用ベース2

SELECT rank, AVG(salary) FROM people GROUP BY rank;

//    rank   ，     rank   (salary)    

SELECT rank, AVG(salary) FROM people GROUP BY rank
HAVING AVG(salary) > 1000;

// group by        having       

SELECT  rank, AVG(salary) FROM people
WHERE rank <> 'Private'
GROUP BY rank HAVING AVG(salary) > 10000;

      AND, OR, NOT

SELECT user_name
FROM user
WHERE (AGE > 18) AND (STATUS='RESIDENT');

SELECT user_name
FROM user
WHERE (AGE >10 AND STATUS='RESIDENT')
OR (AGE > 10 AND STATUS='APPLICANT')

SELECT user_name
FROM user
WHERE NOT (AGE > 18 AND STATUS='RES'

SELECT title
FROM book
WHERE author IS null;

SELECT title
FROM book
WHERE author IN ('Stephen King', 'Richard');

//               in    

SELECT title FROM book
WHERE book_id BETWEEN 1 AND 100;

SELECT name FROM people
WHERE name LIKE 'stac%';