MySQL基本簡單操作02

MySQL基本簡單操作

先進入Mysql容器。

[root@promote ~]# docker exec -it mysql /bin/bash
root@30d60b852cf5:/# mysql -uroot -p000000
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.11 MySQL Community Server - GPL

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Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

新建一個資料庫。

mysql> create database gubeiqing;
Query OK, 1 row affected (0.02 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| gubeiqing          |
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.01 sec)

進入資料庫，新建數據表。

mysql> use gubeiqing;
Database changed
mysql> show tables;
Empty set (0.00 sec)

mysql> create table gubeiqing_table(name varchar(20) not null , age varchar(20) not null);
Query OK, 0 rows affected (0.11 sec)

mysql> show tables;
+---------------------+
| Tables_in_gubeiqing |
+---------------------+
| gubeiqing_table     |
+---------------------+
1 row in set (0.01 sec)

接著給資料庫新增列，基本簡單語法是：ALTER TABLE 表名 add column 列名 列類型 是否為空;。

mysql> desc gubeiqing_table;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| name  | varchar(20) | NO   |     | NULL    |       |
| age   | varchar(20) | NO   |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
2 rows in set (0.01 sec)

mysql> alter table gubeiqing_table add column job varchar(20) not null;
Query OK, 0 rows affected (0.26 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc gubeiqing_table;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| name  | varchar(20) | NO   |     | NULL    |       |
| age   | varchar(20) | NO   |     | NULL    |       |
| job   | varchar(20) | NO   |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

修改列名，基本簡單語法是：ALTER TABLE 表名 change column 原列名 修改後的列名 列類型 是否為空；。

mysql> desc gubeiqing_table;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| name  | varchar(20) | NO   |     | NULL    |       |
| age   | varchar(20) | NO   |     | NULL    |       |
| job   | varchar(20) | NO   |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

mysql> alter table gubeiqing_table change column job gbq_job varchar(20) not null;
Query OK, 0 rows affected (0.11 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc gubeiqing_table;
+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| name    | varchar(20) | NO   |     | NULL    |       |
| age     | varchar(20) | NO   |     | NULL    |       |
| gbq_job | varchar(20) | NO   |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

刪除剛剛新增的列，基本簡單語法是：ALTER TABLE 表名 drop column 列名;。

mysql> desc gubeiqing_table;
+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| name    | varchar(20) | NO   |     | NULL    |       |
| age     | varchar(20) | NO   |     | NULL    |       |
| gbq_job | varchar(20) | NO   |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

mysql> alter table gubeiqing_table drop column gbq_job;
Query OK, 0 rows affected (0.11 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc gubeiqing_table;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| name  | varchar(20) | NO   |     | NULL    |       |
| age   | varchar(20) | NO   |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

然後說一下模糊搜索，就比如現在要在資料庫里查找zhangsan的信息，可是只記得zhang剩下的部分都不記得了，那麼就可以使用模糊搜索，基本簡單語法是：SELECT * from 表名 WHERE 欄位 LIKE '模糊欄位';。

mysql> select * from gubeiqing_table where name like 'zhang%';
+----------+-----+
| name     | age |
+----------+-----+
| zhangsan | 20  |
+----------+-----+
1 row in set (0.01 sec)

%用來表示不記得的部分，是通配符。
除了%之外還有 _表示任何單個字元，[ ]指定範圍或集合中的任何單個字元，[^]不屬於指定範圍或集合的任何單個字元。