常用的sql命令：
SHOW DATABASES;  # 查看有哪些数据库
CREATE DATABASE tedu1 CHARSET utf8; # 创建库
MariaDB [(none)]> SHOW DATABASES;
+--------------------+
| tedu1              |
+--------------------+
USE tedu1;  # 选择数据库
CREATE TABLE bumen(bumen_id int, bumen_name varchar(30)); #建表 30表示字符串长度最大不超过30个字符
SHOW TABLES; # 查看当前库的表
+-----------------+
| bumen           |
+-----------------+
INSERT INTO bumen VALUES(1, "开发部"); # 插入数据
INSERT INTO bumen VALUES(2, "OPS"); # 插入数据
SELECT * FROM bumen; # 查询某表中的数据
+----------+------------+
| bumen_id | bumen_name |
+----------+------------+
|        1 | 开发部     |
|        2 | OPS        |
+----------+------------+
UPDATE bumen SET bumen_name = "DEV" WHERE bumen_id = 1;   # 更新数据
DELETE FROM bumen WHERE bumen_id = 2; # 删除数据
SELECT * FROM bumen;  # 查询数据
+----------+------------+
|        1 | DEV        |
+----------+------------+
DROP TABLE bumen;  # 删表
SHOW TABLES;  # bumen已被删除