-- 需要连接这个数据库表
SELECT * FROM '数据表名'; --查询整个表
SELECT * FROM 'book' WHERE book.id = 1; --查询book表且根据id查找

-- INNER JOIN是全连接
SELECT * FROM book INNER JOIN other; --book表和other表关联在一起（重复N*N）
SELECT * FROM book INNER JOIN other ON book.id = other.id; --ON id相等关联在一起

-- 模糊查询
select * from book where name like; '%王%'

-- LEFT JOIN是左连接
SELECT * FROM book LEFT JOIN other ON book.id = other.id; --左表的保留，匹配右表数据

-- RIGHT JOIN是左连接
SELECT * FROM book RIGHT JOIN other ON book.id = other.id; --右表的保留，匹配左表数据