mysql 基本操作 一

1.mysql 管理语句

1)展示数据库列表

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| data_store         |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
 rows in set (0.00 sec)

mysql> 

2）进入到相应数据库

mysql> use data_store;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed

3）显示表

mysql> show tables;
+----------------------+
| Tables_in_data_store |
+----------------------+
| sec_menu_item        |
| sec_menu_role        |
| sec_role             |
| sec_user             |
| sec_user_copy        |
| sec_user_role        |
| sec_user_test        |
| stream_test_save     |
| test1                |
| test1234             |
| test1_1              |
| test2                |
| test5                |
| test_hdfs_from_mysql |

4）显示表中的列信息

mysql> show columns from test5;
+-------+------------+------+-----+---------+-------+
| Field | Type       | Null | Key | Default | Extra |
+-------+------------+------+-----+---------+-------+
| name  | text       | YES  |     | NULL    |       |
| age   | bigint() | YES  |     | NULL    |       |
+-------+------------+------+-----+---------+-------+
 rows in set (0.00 sec)

5）显示表中的索引信息

mysql> show index from sec_user;
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table    | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| sec_user |           | PRIMARY  |             | id          | A         |            |     NULL | NULL   |      | BTREE      |         |               |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
 row in set (0.00 sec)

6）显示表状态

mysql> show table status from data_store;
mysql> show table status from data_store like 'test%';

2.创建数据库

mysql> create database test;
Query OK,  row affected (0.01 sec)
删除数据库

mysql> drop database test;
Query OK, 0 rows affected (0.01 sec)

3.MySQL 数据类型

4.创建表

create table runoob_tb1(
runoob_id int not null auto_increment,
runoob_title varchar() not null,
runoob_author varchar() not null,
submission_date date,
primary key (runoob_id)
)engine=innodb default charset=utf8;

not null ：设置对应字段不能为null，若插入的值为null，则会报错

primary key 指定的是主键，一般是自增的

5.删除表

mysql> drop table runoob_tb1;
Query OK,  rows affected (0.07 sec)

6.插入数据

insert into runoob_tb1(
runoob_title,runoob_author,submission_date
)
values
("学习python","菜鸟教程",now()),
("学习scala","菜鸟教程",now());

Query OK,  rows affected,  warnings (0.00 sec)
Records:   Duplicates:   Warnings: 

7.删除数据

MariaDB [jason]> delete from runoob_tbl where runoob_id=;
Query OK,  row affected (0.00 sec)