1、创建表
mysql> create table employee (
-> id int(1) comment '员工编号',
-> name varchar(6) comment '员工名字',
-> gender varchar(2) comment '员工性别',
-> salary int (4) comment '员工薪资');
Query OK, 0 rows affected (0.01 sec)
2、插入数据
insert employee values(1,'张三','男',2000);
insert into employee values (2,'李四','男',1000);
insert into employee values (3,'王五','女',4000)
*问题：插入记录报错
解决：将字符集换成 utf8mb4 即可，对mysql来说utf8mb4才是真正的utf8, 支持4个字节的字符，也兼容mysql的自己的utf8 。
执行如下语句：该语句直接将表的字符集设置为utf8mb4，并将表中字符类型的字段也转换为utf8mb4。
ALTER TABLE
user_infoCONVERT TO CHARACTER SET utf8mb4;
3、修改表数据
① mysql> update employee set salary=5000;
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3 Changed: 3 Warnings: 0② mysql> update employee set salary=3000 where name='张三';
Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0③ mysql> update employee set salary=4000,gender='女' where name='李四';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0④mysql> update employee set salary=salary+1000 where name='王五';
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0
