编辑代码

CREATE DATABASE test1;
use test1;
CREATE TABLE student (
	id int,
	name varchar(255),
	address varchar(255),
	city varchar(255)
);

INSERT INTO student VALUES (1, '刘一', '郑十家隔壁', '河南');
INSERT INTO student VALUES (2, '陈二',  '李四家隔壁', '安徽');
INSERT INTO student VALUES (3, '张三',  '白娘子家隔壁', '杭州');
INSERT INTO student VALUES (4, '李四',  '许仙家隔壁', '杭州');
INSERT INTO student VALUES (5, '王五',  '李四家隔壁', '杭州');
INSERT INTO student VALUES (6, '赵六',  '赵六家隔壁', '杭州');
INSERT INTO student VALUES (7, '孙七',  '张三家隔壁', '杭州');
INSERT INTO student VALUES (8, '周八',  '雷峰塔附近', '杭州');
INSERT INTO student VALUES (9, '吴九',  '孙七家隔壁', '杭州');
INSERT INTO student VALUES (10, '郑十',  '周八家隔壁', '杭州');
INSERT INTO student( id, name) VALUES(11,'测试名称2'),(12,'测试名称2');
update student set name = 'ttt' where id = 11;

SELECT '/n=====================';

SELECT city,avg(id) from student group by city;

SELECT '/n=====================';


DELETE FROM student where id < 8;
SELECT * FROM student;
SELECT id FROM student where id = 8;

show DATABASEs;

use mysql;
show TABLES;


drop table  if exists slow_log ;
show TABLES;