mysql數據庫入門命令 --增、刪、查、改
阿新 • • 發佈：2018-09-02
記錄 數據庫 chan col databases with 生成 command creat 添加數據庫
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
...... #省略部分內容
5 rows in set (0.00 sec)
[root@localhost ~]# mysql -uroot -p #進入mysql數據表Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
...... #省略部分內容
Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.
mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec)
mysql> create database school; #創建新庫‘school
Query OK, 1 row affected (0.00 sec)
mysql> show databases; #查看所有庫
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| school |
| sys |
5 rows in set (0.00 sec)
添加數據表
mysql>use school; mysql> create table info (id int not null,name char(6),score decimal(5,2),age int(4))； Query OK, 0 rows affected (0.04 sec) mysql> desc info; #查看表結構 +-------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+--------------+------+-----+---------+-------+ | id | int(11) | NO | | NULL | | | name | char(6) | YES | | NULL | | | score | decimal(5,2) | YES | NULL | | | age | int(4) | YES | | NULL | | +-------+--------------+------+-----+---------+-------+ 添加數據表內容 mysql> insert into info (id,name,score,age)values(1,‘張三‘,88,33); Query OK, 1 row affected (0.01 sec) mysql> insert into info (id,name,score,age)values(2,‘李四‘,48,31); Query OK, 1 row affected (0.01 sec) mysql> insert into info (id,name,score,age)values(3,‘王五‘,68,27); Query OK, 1 row affected (0.00 sec) mysql> select * from info; #查看表內容 +----+--------+-------+------+ | id | name | score | age | +----+--------+-------+------+ | 1 | 張三 | 88.00 | 33 | | 2 | 李四 | 48.00 | 31 | | 3 | 王五 | 68.00 | 27 | +----+--------+-------+------+ 添加表列 mysql> alter table info add column score decimal(5,2); Query OK, 0 rows affected (0.05 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> select * from info; #查看表內容 +----+--------+--------+-------+ | id | name | hobbly | score | +----+--------+--------+-------+ | 1 | zl | 看書 | NULL | | 2 | 李四 | 上網 | NULL | | 5 | kl | 遊泳 | NULL | +----+--------+--------+-------+ 更改數據 mysql> update info set score=82 where id=1; #更改id=1的學生成績為82分 Query OK, 1 row affected (0.01 sec) Rows matched: 1 Changed: 1 Warnings: 0 mysql> select * from info; #查看更改效果 +----+--------+-------+------+ | id | name | score | age | +----+--------+-------+------+ | 1 | 張三 | 82.00 | 33 | | 2 | 李四 | 48.00 | 31 | | 3 | 王五 | 68.00 | 27 | +----+--------+-------+------+ 刪除數據表 mysql> drop table info; Query OK, 0 rows affected (0.02 sec) mysql> show tables; #查看是否刪除 Empty set (0.00 sec) #已經刪除（空表） 刪除庫 mysql> drop database school; Query OK, 0 rows affected (0.01 sec) mysql> show databases; #查看school數據庫是否刪除 +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 刪除表列（記錄條數） mysql> delete from info where hobbly=1; Query OK, 1 row affected (0.01 sec) mysql> select * from info; +----+--------+-------+------+--------+ | id | name | score | age | hobbly | +----+--------+-------+------+--------+ | 1 | 張三 | 82.00 | 33 | 3 | | 2 | 李四 | 48.00 | 31 | 5 | | 3 | 王五 | 68.00 | 27 | 4 | | 2 | ff | 55 | 44 | 2 | | 3 |ww | 33 |3 1 | 3 | +----+--------+-------+------+--------+ 刪除表列（字段） mysql> select * from info; #查看數據表 +----+--------+-------+--------+ | id | name | score | hobbly | +----+--------+-------+--------+ | 1 | zl | 88 | 看書 | | 2 | 李四 | 68 | 上網 | | 5 | kl | 88 | 遊泳 | +----+--------+-------+--------+ mysql> alter table info drop column score; #用alter刪除表列 mysql> select * from info; #再次查看數據表 +----+--------+--------+ | id | name | hobbly | +----+--------+--------+ | 1 | zl | 看書 | | 2 | 李四 | 上網 | | 5 | kl | 遊泳 | +----+--------+--------+
mysql數據庫入門命令 --增、刪、查、改