1、連接mysql

1. 連接本機(jī)

   mysql -u root -p

2. 連接遠(yuǎn)程主機(jī)

   mysql -h 192.168.1.% -u root -p

3. 退出

   exit;

2、修改密碼

格式：alter user 用戶名@主機(jī)地址 identified by '新密碼';

1. 將root密碼改為newroot

   alter user root@local identified by 'newroot';

2. 查看用戶主機(jī)地址方法

   use mysql;
   select user,host from user;

3、管理用戶

可以管理mysql數(shù)據(jù)庫中的user表來管理用戶。

對(duì)于用戶方面的管理，最好對(duì)用戶授予不同的權(quán)限來管理用戶。

增加tom用戶，密碼為tom，可在任何主機(jī)登錄：

create user 'tom'@localhost identified by 'tom';
create user 'tom1'@'192.168.1.%' identified by 'tom1';

4、管理數(shù)據(jù)庫

1. 顯示數(shù)據(jù)庫

   show databases;

   注：數(shù)據(jù)庫亂碼問題

   1. 修改/etc/my.cnf配置文件:character-set-server=utf8

   2. Java連接mysql的配置文件中：

      jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8;

    

2. 創(chuàng)建數(shù)據(jù)庫

   create database db_name;

    

3. 刪除數(shù)據(jù)庫

   drop database if exists db_name;

4. 使用數(shù)據(jù)庫

   mysql> use db_name;
   Database changed

5. 當(dāng)前選擇的數(shù)據(jù)庫

   select database();

   MySQL中select命令類似于其他編程語言里的print或者write，你可以用它來顯示一個(gè)字符串、數(shù)字、數(shù)學(xué)表達(dá)式的結(jié)果等等。部分select命令如下：

   select version();               // 顯示mysql版本
   select now();                   // 顯示當(dāng)前時(shí)間
   select current_date;            // 顯示年月日
   select ((4 * 7) / 10 ) + 23;    // 計(jì)算

5、管理表

1. 顯示所有表

   show tables;

2. 查看表結(jié)構(gòu)

   （1）方式一：

   mysql> desc orders;
   +------------+----------+------+-----+---------+----------------+
   | Field     | Type     | Null | Key | Default | Extra         |
   +------------+----------+------+-----+---------+----------------+
   | order_num  | int(11)  | NO   | PRI | NULL   | auto_increment |
   | order_date | datetime | NO   |     | NULL   |               |
   | cust_id   | int(11)  | NO   | MUL | NULL   |               |
   +------------+----------+------+-----+---------+----------------+
   3 rows in set (0.24 sec)

   （2）方式二：

   mysql> show columns from orders;
   +------------+----------+------+-----+---------+----------------+
   | Field     | Type     | Null | Key | Default | Extra         |
   +------------+----------+------+-----+---------+----------------+
   | order_num  | int(11)  | NO   | PRI | NULL   | auto_increment |
   | order_date | datetime | NO   |     | NULL   |               |
   | cust_id   | int(11)  | NO   | MUL | NULL   |               |
   +------------+----------+------+-----+---------+----------------+
   3 rows in set (0.00 sec)

   （3）方式三：

   mysql> show create table orders\G;
   *************************** 1. row ***************************
          Table: orders
   Create Table: CREATE TABLE `orders` (
     `order_num` int(11) NOT NULL AUTO_INCREMENT,
     `order_date` datetime NOT NULL,
     `cust_id` int(11) NOT NULL,
     PRIMARY KEY (`order_num`),
     KEY `fk_orders_customers` (`cust_id`),
     CONSTRAINT `fk_orders_customers` FOREIGN KEY (`cust_id`) REFERENCES `customers` (`cust_id`)
   ) ENGINE=InnoDB AUTO_INCREMENT=20011 DEFAULT CHARSET=utf8
   1 row in set (0.00 sec)
   ?
   ERROR: 
   No query specified

   （4）方式四：

   mysql> show full fields from orders;
   +------------+----------+-----------+------+-----+---------+----------------+---------------------------------+---------+
   | Field     | Type     | Collation | Null | Key | Default | Extra         | Privileges                     | Comment |
   +------------+----------+-----------+------+-----+---------+----------------+---------------------------------+---------+
   | order_num  | int(11)  | NULL     | NO   | PRI | NULL   | auto_increment | select,insert,update,references |         |
   | order_date | datetime | NULL     | NO   |     | NULL   |               | select,insert,update,references |         |
   | cust_id   | int(11)  | NULL     | NO   | MUL | NULL   |               | select,insert,update,references |         |
   +------------+----------+-----------+------+-----+---------+----------------+---------------------------------+---------+
   3 rows in set (0.00 sec)

   （5）方式五：

   mysql> show fields from orders;
   +------------+----------+------+-----+---------+----------------+
   | Field     | Type     | Null | Key | Default | Extra         |
   +------------+----------+------+-----+---------+----------------+
   | order_num  | int(11)  | NO   | PRI | NULL   | auto_increment |
   | order_date | datetime | NO   |     | NULL   |               |
   | cust_id   | int(11)  | NO   | MUL | NULL   |               |
   +------------+----------+------+-----+---------+----------------+
   3 rows in set (0.00 sec)

   （6）方式六：查看表中某個(gè)字段

   mysql> desc orders order_num;
   +-----------+---------+------+-----+---------+----------------+
   | Field     | Type   | Null | Key | Default | Extra         |
   +-----------+---------+------+-----+---------+----------------+
   | order_num | int(11) | NO   | PRI | NULL   | auto_increment |
   +-----------+---------+------+-----+---------+----------------+
   1 row in set (0.00 sec)

   （7）方式七：查看表中索引

   mysql> show index from orders\G;
   *************************** 1. row ***************************
           Table: orders
      Non_unique: 0
        Key_name: PRIMARY
    Seq_in_index: 1
     Column_name: order_num
       Collation: A
     Cardinality: 5
        Sub_part: NULL
          Packed: NULL
            Null: 
      Index_type: BTREE
         Comment: 
   Index_comment: 
   *************************** 2. row ***************************
           Table: orders
      Non_unique: 1
        Key_name: fk_orders_customers
    Seq_in_index: 1
     Column_name: cust_id
       Collation: A
     Cardinality: 4
        Sub_part: NULL
          Packed: NULL
            Null: 
      Index_type: BTREE
         Comment: 
   Index_comment: 
   2 rows in set (0.00 sec)
   ?
   ERROR: 
   No query specified

3. 創(chuàng)建表：建立一個(gè)名為test的表

   mysql> create table test(
      -> id INT(11) NOT NULL AUTO_INCREMENT,
      -> name VARCHAR(255) NOT NULL,
      -> PRIMARY KEY (id)
      -> );
   Query OK, 0 rows affected (0.44 sec)

4. 刪除表

   mysql> drop table if exists test;
   Query OK, 0 rows affected (0.20 sec)

5. 向表中插入數(shù)據(jù)：

   格式：insert into 表名 ( 字段名1,···, 字段名n ) values ( 值1, ···, 值n );

   mysql> insert into test (name) values ("zhangsan");
   Query OK, 1 row affected (0.14 sec)
   ?
   mysql> select * from test;
   +----+----------+
   | id | name     |
   +----+----------+
   |  1 | zhangsan |
   +----+----------+
   1 row in set (0.02 sec)

   插入多條記錄：

   mysql> insert into test (name) values ("lisi"),("xiaoming");
   Query OK, 2 rows affected (0.04 sec)
   Records: 2  Duplicates: 0  Warnings: 0
   ?
   mysql> select * from test;
   +----+----------+
   | id | name     |
   +----+----------+
   |  1 | zhangsan |
   |  2 | lisi     |
   |  3 | xiaoming |
   +----+----------+
   3 rows in set (0.00 sec)

6. 查詢表數(shù)據(jù)

   格式： select 字段1, ···, 字段n from 表名 where 表達(dá)式

   （1）查詢表所有：

   mysql> select * from test;
   +----+----------+
   | id | name     |
   +----+----------+
   |  1 | zhangsan |
   |  2 | lisi     |
   |  3 | xiaoming |
   +----+----------+
   3 rows in set (0.00 sec)

   （2）查詢前兩行：

   mysql> select * from test limit 2;
   +----+----------+
   | id | name     |
   +----+----------+
   |  1 | zhangsan |
   |  2 | lisi     |
   +----+----------+
   2 rows in set (0.03 sec)

7. 刪除表數(shù)據(jù)

   格式：delete from 表名 where 表達(dá)式

   mysql> delete from test where id = 2;
   Query OK, 1 row affected (0.13 sec)
   ?
   mysql> select * from test;
   +----+----------+
   | id | name     |
   +----+----------+
   |  1 | zhangsan |
   |  3 | xiaoming |
   +----+----------+
   2 rows in set (0.00 sec)

8. 修改表數(shù)據(jù)

   格式：UPDATE [LOW_PRIORITY] tbl_name SET col_name1=expr1 [, col_name2=expr2 ...] [WHERE where_definition] [ORDER BY ...] [LIMIT row_count]

   • UPDATE語法可以用新值更新原有表行中的各列；

   • SET子句指示要修改哪些列和要給予哪些值；

   • WHERE子句指定應(yīng)更新哪些行。如果沒有WHERE子句，則更新所有的行；

   • 如果指定了ORDER BY子句，則按照被指定的順序?qū)π羞M(jìn)行更新；

   • LIMIT子句用于給定一個(gè)限值，限制可以被更新的行的數(shù)目。

   mysql> select * from test;
   +----+----------+
   | id | name     |
   +----+----------+
   |  1 | zhangsan |
   |  3 | xiaoming |
   |  4 | lisi     |
   +----+----------+
   3 rows in set (0.00 sec)
   ?
   mysql> update test set name = "xiaohong" where id = 3;
   Query OK, 1 row affected (0.04 sec)
   Rows matched: 1  Changed: 1  Warnings: 0
   ?
   mysql> select * from test;
   +----+----------+
   | id | name     |
   +----+----------+
   |  1 | zhangsan |
   |  3 | xiaohong |
   |  4 | lisi     |
   +----+----------+
   3 rows in set (0.00 sec)

9. 增加字段

   格式：ALTER TABLE tb_name ADD col_name1 column_definition [FIRST | AFTER col_name]; [FIRST | AFTER col_name] 指定位置關(guān)系，F(xiàn)IRST表示在第一列，AFTER col_name表示在 col_name 列之后；

   mysql> alter table test add column(
      -> phone INT(11) NULL,
      -> addr VARCHAR(50)
      -> );
   Query OK, 0 rows affected (0.32 sec)
   Records: 0  Duplicates: 0  Warnings: 0
   ?
   mysql> desc test;
   +-------+--------------+------+-----+---------+----------------+
   | Field | Type         | Null | Key | Default | Extra         |
   +-------+--------------+------+-----+---------+----------------+
   | id   | int(11)     | NO   | PRI | NULL   | auto_increment |
   | name  | varchar(255) | NO   |     | NULL   |               |
   | phone | int(11)     | YES  |     | NULL   |               |
   | addr  | varchar(50)  | YES  |     | NULL   |               |
   +-------+--------------+------+-----+---------+----------------+
   4 rows in set (0.00 sec)

10. 刪除列

    格式：ALTER TABLE tb_name DROP [COLUMN] col_name1 [, DROP col_name2 ...];

    • [COLUMN] 關(guān)鍵字可有可無；

    • 刪除多列時(shí)需使用DROP關(guān)鍵字，不可直接用 , 分隔；

11. 修改字段

    （1）修改列

    ALTER TABLE tb_name
    CHANGE [COLUMN] old_col_name new_col_name column_definition #注意一定要指定類型
    [FIRST|AFTER col_name];

    （2）修改列類型

    ALTER TABLE tb_name
    MODIFY col_name column_definition;

12. 添加約束

    （1）添加主鍵約束

    格式：ALTER TABLE tb_name ADD [CONSTRAINT [symbol]] PRIMARY KEY index_type;

    • [CONSTRAINT [symbol]] constraint 關(guān)鍵字，symbol 表示約束別名，可有可無，mysql會(huì)自動(dòng)創(chuàng)建；

    • [index_type] 索引類型 包含 {B+TREE | HASH}，存儲(chǔ)引擎為InnoDB時(shí)只能使用B+TREE，默認(rèn)值為B+TREE，但是InnoDB可以有自適應(yīng)hash索引、即索引中的索引；

    （2）添加唯一約束

    格式：ALTER TABLE tb_name ADD [CONSTRAINT [symbol]] UNIQUE [INDEX|KEY] [index_name] [index_type] (index_col_name,...);

    • [INDEX|KEY] 說明是 INDEX 還是 KEY，關(guān)于INDEX 和 KEY 的區(qū)別參考：Mysql中的key和index的區(qū)別

    • [index_name] 索引名稱，好像 和[CONSTRAINT [symbol]] 沒有區(qū)別；

    • [index_type] 索引類型， 包含 {BTREE | HASH}

    （3）刪除約束

    格式：alter table tb_name drop key index_name;

13. 添加索引

    （1）加索引

    格式：

    #普通索引
    ALTER TABLE tb_name
    ADD {INDEX|KEY} [index_name](key_part,...) [index_option] ...
    ?
    #全文索引
    ALTER TABLE tbl_name
    ADD FULLTEXT [INDEX|KEY] [index_name](key_part,...) [index_option] ...
    ?
    #空間索引
    ALTER TABLE tbl_name
    ADD SPATIAL [INDEX|KEY] [index_name](key_part,...) [index_option] ...
    ?
    key_part:
       col_name [(length)] [ASC|DESC]
    ?
    index_type:
        USING {BTREE|HASH}
    ?
    index_option:
       KEY_BLOCK_SIZE [=] value
      | index_type
      | WITH PARSER parser_name
      | COMMENT 'string'