SQL中的 MAX() 函数返回指定列的最大值
SELECT MAX(column_name) FROM table_name;
演示数据
先在 MySQL 数据库运行下面的语句创建测试数据
CREATE DATABASE IF NOT EXISTS ddkk default character set utf8mb4 collate utf8mb4_unicode_ci;
USE ddkk;
DROP TABLE IF EXISTS lession;
CREATE TABLE lession (
id int(11) NOT NULL PRIMARY KEY AUTO_INCREMENT,
name varchar(32) default '',
views int(11) NOT NULL default '0',
created_at DATETIME
);
INSERT INTO lession(id,name,views,created_at) VALUES
(1, 'Python DDKK.COM 弟弟快看',981,'2017-04-18 13:52:03'),
(2, 'Scala DDKK.COM 弟弟快看',73,'2017-04-18 16:03:32'),
(3, 'Ruby DDKK.COM 弟弟快看',199,'2017-05-01 06:16:14');
使用SELECT * FROM lession; 运行结果如下
+----+---------------------+-------+--------------------+
| id | name | views | created_at |
+----+---------------------+-------+--------------------+
| 1 | Python DDKK.COM 弟弟快看 | 981 | 2017-04-18 13:52:03 |
| 2 | Scala DDKK.COM 弟弟快看 | 73 | 2017-04-18 16:03:32 |
| 3 | Ruby DDKK.COM 弟弟快看 | 199 | 2017-05-01 06:16:14 |
+----+---------------------+-------+--------------------+
总共有3 条记录
SQL MAX() 范例
下面的SQL 语句返回 访问量 ( views ) 的最大值
SELECT MAX(views) FROM lession;
运行结果如下
mysql> SELECT MAX(views) FROM lession;
+------------+
| MAX(views) |
+------------+
| 981 |
+------------+