Linux运维必会MySQL30道基础命令
Linux运维必会MySQL 30道基础命令
老男孩老师教学与培训核心思想：重目标、重思路、重方法、重实践、重习惯、重总结。
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==========================================
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http://oldboy.blog.51cto.com
文档信息：
文档版本：Version 1.6
文档作用：课后总结
修改记录：2015-12-21
系统环境：CentOS release 6.7 (Final)
技术交流：http://yulianhui.blog.51cto.com/
目 录
3.创建GBK字符集的数据库oldboy，并查看已建库的完整语句。... 3
4.创建用户oldboy，使之可以管理数据库oldboy。... 4
8.创建一innodb引擎字符集为GBK表test，字段为id和namevarchar(16)，查看建表结构及SQL语句。... 6
10.批量插入数据 2,老男孩，3,etiantian。要求中文不能乱码。... 8
11.查询插入的所有记录，查询名字为oldboy的记录。查询id大于1的记录。... 8
12.把数据id等于1的名字oldboy更改为oldgirl。... 10
13.在字段name前插入age字段，类型tinyint(2)。... 10
18.把GBK字符集修改为UTF8（可选，注意，此题有陷阱）。... 14
20.MySQL内中文数据乱码的原理及如何防止乱码？（可选）。... 19
21.在把id列设置为主键，在Name字段上创建普通索引。... 20
22.在字段name后插入手机号字段(shouji)，类型char(11)。... 21
27.对Name列的前6个字符以及手机列的前8个字符组建联合索引。... 26
28.查询手机号以135开头的，名字为oldboy的记录（此记录要提前插入）。... 28
29.查询上述语句的执行计划（是否使用联合索引等）。... 28
数据库的重要性是所有技术里最核心最需要掌握的(理解原理，并且被面试时能清晰的表达出来)，直接决定运维人员薪水的高低！
所有题都要给出专业的解答方案，不是很水的那种泛泛的解答。
1.登陆数据库。
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mysql-uroot -poldboy123 -S
/data/3306/mysql
.sock
Welcometo the MySQL monitor. Commands end with; or \g.
YourMySQL connection
id
is 12
Serverversion: 5.5.32-log Source distribution
Copyright(c) 2000, 2013, Oracle and
/or
its affiliates. All rights reserved.
Oracleis 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>
|
2.查看数据库版本及当前登录用户是什么。
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#查看数据库版本
mysql>
select
version();
+------------+
|version() |
+------------+
|5.5.32-log |
+------------+
1row
in
set
(0.00 sec)
#查看当前登录用户
mysql>
select
user();
+----------------+
|user() |
+----------------+
|root@localhost |
+----------------+
1row
in
set
(0.00 sec)
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3.创建GBK字符集的数据库oldboy，并查看已建库的完整语句。
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mysql>create database oldboy character
set
gbk collate gbk_chinese_ci;
QueryOK, 1 row affected (0.00 sec)
mysql>show databases;
+--------------------+
|Database |
+--------------------+
|information_schema |
|mysql |
|oldboy |
|performance_schema |
+--------------------+
4rows
in
set
(0.00 sec)
mysql>
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#查看已建库的完整语句
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mysql>show create database oldboy\G
***************************1. row ***************************
Database: oldboy
CreateDatabase: CREATE DATABASE `oldboy` /*!40100 DEFAULT CHARACTER SET gbk */
1row
in
set
(0.00 sec)
|
4.创建用户oldboy，使之可以管理数据库oldboy。
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mysql>grant all on oldboy.* to oldboy@
'localhost'
identified by
'123'
;
QueryOK, 0 rows affected (0.00 sec)
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5.查看创建的用户oldboy拥有哪些权限。
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mysql>show grants
for
oldboy@
'localhost'
\G
***************************1. row ***************************
Grantsfor oldboy@localhost: GRANT USAGE ON *.* TO
'oldboy'
@
'localhost'
IDENTIFIED BYPASSWORD
'*23AE809DDACAF96AF0FD78ED04B6A265E05AA257'
***************************2. row ***************************
Grantsfor oldboy@localhost: GRANT ALL PRIVILEGES ON`oldboy`.* TO
'oldboy'
@
'localhost'
2rows
in
set
(0.00 sec)
|
6.查看当前数据库里有哪些用户。
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mysql>
select
user,host from mysql.user;
+--------+-----------+
|user | host |
+--------+-----------+
|rep | 10.0.0.% |
|root | 127.0.0.1 |
|oldboy | localhost |
|root | localhost |
+--------+-----------+
4rows
in
set
(0.00 sec)
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6.进入oldboy数据库
mysql>use oldboy;
Databasechanged
mysql>select database();
+------------+
|database() |
+------------+
| oldboy |
+------------+
1row in set (0.00 sec)
8.创建一innodb引擎字符集为GBK表test，字段为id和namevarchar(16)，查看建表结构及SQL语句。
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mysql>create table
test
(
->
id
int(4),
-> name varchar(16)
-> ) ENGINE=innodb default charset=gbk;
QueryOK, 0 rows affected (0.01 sec)
mysql>show tables;
+------------------+
|Tables_in_oldboy |
+------------------+
|
test
|
+------------------+
1row
in
set
(0.00 sec)
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#查看表结构：方法一
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mysql>desc
test
;
+-------+-------------+------+-----+---------+-------+
|Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
|
id
| int(4) | YES | | NULL | |
|name | varchar(16) | YES | |NULL | |
+-------+-------------+------+-----+---------+-------+
2rows
in
set
(0.00 sec)
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#查看表结构：方法二
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mysql>show columns from
test
;
+-------+-------------+------+-----+---------+-------+
|Field | Type | Null | Key |Default | Extra |
+-------+-------------+------+-----+---------+-------+
|
id
| int(4) | YES | | NULL | |
|name | varchar(16) | YES | |NULL | |
+-------+-------------+------+-----+---------+-------+
2rows
in
set
(0.00 sec)
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#查看表结构sql语句
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mysql>show create table
test
\G
***************************1. row ***************************
Table:
test
CreateTable: CREATE TABLE `
test
` (
`
id
` int(4) DEFAULT NULL,
`name` varchar(16) DEFAULT NULL
)ENGINE=InnoDB DEFAULT CHARSET=gbk
1row
in
set
(0.00 sec)
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9.插入一条数据 1,oldboy
mysql>insert into test values(1,'oldboy');
Query OK, 1 row affected (0.00 sec)
mysql> select * from test;
+------+--------+
| id |name |
+------+--------+
| 1 | oldboy |
+------+--------+
1 row in set (0.00 sec)
10.批量插入数据 2,老男孩，3,etiantian。要求中文不能乱码。
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mysql> insert into
test
values(2,
'老男孩'
),(3,
'etiantian'
);
Query OK, 2 rows affected (0.01 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql>
select
* from
test
;
+------+-----------+
|
id
|name |
+------+-----------+
| 1 |oldboy |
| 2 | 老男孩 |
| 3 | etiantian |
+------+-----------+
3 rows
in
set
(0.00 sec)
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11.查询插入的所有记录，查询名字为oldboy的记录。查询id大于1的记录。
（1）查询插入的所有记录
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mysql>
select
* from
test
;
+------+-----------+
|
id
|name |
+------+-----------+
| 1 |oldboy |
| 2 | 老男孩 |
| 3 | etiantian |
+------+-----------+
3 rows
in
set
(0.00 sec)
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（2）查询名字为oldboy的记录
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mysql>
select
* from
test
where name=
'oldboy'
;
+------+--------+
|
id
| name |
+------+--------+
| 1 |oldboy |
+------+--------+
1 row
in
set
(0.01 sec)
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（3）查询id大于1的记录
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mysql>
select
* from
test
where
id
>1;
+------+-----------+
|
id
|name |
+------+-----------+
| 2 | 老男孩 |
| 3 |etiantian |
+------+-----------+
2 rows
in
set
(0.00 sec)
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12.把数据id等于1的名字oldboy更改为oldgirl。
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mysql> update
test
set
name=
'oldgirl'
whereid=1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql>
select
* from
test
;
+------+-----------+
|
id
|name |
+------+-----------+
| 1 |oldgirl |
| 2 | 老男孩 |
| 3 |etiantian |
+------+-----------+
3 rows
in
set
(0.00 sec)
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13.在字段name前插入age字段，类型tinyint(2)。
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mysql> alter table
test
add age tinyint(2)after
id
;
Query OK, 3 rows affected (0.01 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> desc
test
;
+-------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
|
id
|int(4) | YES | | NULL | |
| age |tinyint(2) | YES | |NULL | |
| name |varchar(16) | YES | | NULL | |
+-------+-------------+------+-----+---------+-------+
rows
in
set
(0.00 sec)
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14.备份oldboy库及MySQL库。
退出mysql数据库在命令行输入
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mysqldump -uroot -poldboy123 -S
/data/3306/mysql
.sock--events -B oldboy mysql >
/opt/bak
.sql
[root@db02 ~]
# ll /opt/bak.sql
-rw-r--r-- 1 root root 529737 Dec 21 16:55
/opt/bak
.sql
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15.删除表中的所有数据，并查看。
delete是逻辑删除表中的数据，一列一列的删除表中数据，速度比较慢
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mysql> delete from
test
;
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truncate是物理删除表中的数据，一次性全部都给清空表中数据，速度很快
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mysql> truncate table
test
;
Query OK, 0 rows affected (0.00 sec)
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##查看结果
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mysql>
select
* from
test
;
Empty
set
(0.00 sec)
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16.删除表test和oldboy数据库并查看
#删除表test
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mysql> show tables;
+------------------+
| Tables_in_oldboy |
+------------------+
|
test
|
+------------------+
1 row
in
set
(0.00 sec)
mysql> drop table
test
;
Query OK, 0 rows affected (0.01 sec)
mysql> show tables;
Empty
set
(0.00 sec)
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#删除数据库oldboy
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mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| oldboy |
| performance_schema |
+--------------------+
4 rows
in
set
(0.00 sec)
mysql> drop database oldboy;
Query OK, 0 rows affected (0.00 sec)
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##查看结果
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mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
+--------------------+
3 rows
in
set
(0.00 sec)
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17.Linux命令行恢复以上删除的数据。
#退出mysql数据库在命令输入命令
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mysql -uroot -poldboy123 -S
/data/3306/mysql
.sock<
/opt/bak
.sql
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#登录数据库并查看结果
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mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| oldboy |
| performance_schema |
+--------------------+
4 rows
in
set
(0.00 sec)
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#查看test表的数据
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mysql>
select
* from oldboy.
test
;
+------+------+-----------+
|
id
| age | name |
+------+------+-----------+
| 1 | NULL |oldgirl |
| 2 | NULL | 老男孩|
| 3 | NULL |etiantian |
+------+------+-----------+
3 rows
in
set
(0.00 sec)
|
18.把GBK字符集修改为UTF8（可选，注意，此题有陷阱）。
#首先查看一下
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mysql> show variables like
'character_set%'
;
+--------------------------+-------------------------------------------+
| Variable_name | Value |
+--------------------------+-------------------------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir |
/application/mysql-5
.5.32
/share/charsets/
|
+--------------------------+-------------------------------------------+
8 rows
in
set
(0.00 sec)
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###人品好字符集都是utf8O(∩_∩)O哈哈~
#现在开始模拟gbk字符集测试环境
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mysql>
set
global character_set_database = gbk;
mysql> quit；
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[root@db02 ~]
# mysql -uroot -poldboy -S/data/3306/mysql.sock
mysql> show variables like
'character_set%'
;
+--------------------------+-------------------------------------------+
| Variable_name | Value |
+--------------------------+-------------------------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | gbk |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir |
/application/mysql-5
.5.32
/share/charsets/
|
+--------------------------+-------------------------------------------+
8 rows
in
set
(0.00 sec)
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##现在把字符集修改成utf8会了吗？
操作一下吧-_-!!!
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mysql>
set
global character_set_database = utf8;
Query OK, 0 rows affected (0.00 sec)
mysql> quit;
Bye
|
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mysql> show variables like
'character_set%'
;
+--------------------------+-------------------------------------------+
| Variable_name | Value |
+--------------------------+-------------------------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir |
/application/mysql-5
.5.32
/share/charsets/
|
+--------------------------+-------------------------------------------+
8 rows
in
set
(0.00 sec)
|
#这就完成了！
19.MySQL密码丢了，如何找回实战？
#查看一下进程是否服务在运行
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[root@db02 ~]
# ps -ef |grep 3306
root 1466 1 0 10:36 ? 00:00:00
/bin/sh/application/mysql/bin/mysqld_safe
--defaults-
file
=
/data/3306/my
.cnf
mysql 2190 1466 0 10:36 ? 00:00:11
/application/mysql-5
.5.32
/bin/mysqld
--defaults-
file
=
/data/3306/my
.cnf--basedir=
/application/mysql
--datadir=
/data/3306/data--plugin-dir
=
/application/mysql/lib/plugin
--user=mysql--log-error=
/data/3306/mysql_oldboy3306
.err --
open
-files-limit=1024--pid-
file
=
/data/3306/mysqld
.pid --socket=
/data/3306/mysql
.sock --port=3306
root 3935 3703 0 16:16 pts
/3
00:00:00 mysql -uroot -px xxxxxxx -S
/data/3306/mysql
.sock
root 4099 4008 0 17:17 pts
/1
00:00:00
grep
--color=auto 3306
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#杀死进程pid号
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[root@db02~]
# kill 1466
[root@db02~]
# kill 1466
-
bash
:
kill
: (1466) - No such process
[root@db02 ~]
# ps -ef |grep 3306
root 3935 3703 0 16:16 pts
/3
00:00:00 mysql -uroot -px xxxxxxx -S
/data/3306/mysql
.sock
root 4104 4008 0 17:17 pts
/1
00:00:00
grep
--color=auto 3306
|
[root@db02 ~]# pkill mysql ###<====这里别忘了杀死-_-!!
#启动mysql实例3306跳过输入用户密码文件
[root@db02 ~]# mysqld_safe--defaults-file=/data/3306/my.cnf --skip-grant-tables &>/dev/null & ##<=====放在后台运行
[1] 4697
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[root@db02 ~]
# ps -ef |grep 3306
root 4697 4008 1 17:24 pts
/1
00:00:00
/bin/sh/application/mysql/bin/mysqld_safe
--defaults-
file
=
/data/3306/my
.cnf--skip-grant-tables
mysql 5434 4697 2 17:24 pts
/1
00:00:00
/application/mysql-5
.5.32
/bin/mysqld
--defaults-
file
=
/data/3306/my
.cnf--basedir=
/application/mysql
--datadir=
/data/3306/data
--plugin-
dir
=
/application/mysql/lib/plugin--user
=mysql --skip-grant-tables --log-error=
/data/3306/mysql_oldboy3306
.err--
open
-files-limit=1024 --pid-
file
=
/data/3306/mysqld
.pid--socket=
/data/3306/mysql
.sock --port=3306
root 5453 4008 0 17:24 pts
/1
00:00:00
grep
--color=auto 3306
[root@db02 ~]
# netstat -ltunp |grep 3306
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 5434
/mysqld
|
#登录到数据库3306实例
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[root@db02 ~]
# mysql -S /data/3306/mysql.sock
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection
id
is 1
Server version: 5.5.32-log Source distribution
Copyright (c) 2000, 2013, Oracle and
/or
itsaffiliates. All rights reserved.
Oracle is a registered trademark of OracleCorporation and
/or
its
affiliates. Other names may be trademarks oftheir respective
owners.
Type
'help;'
or
'\h'
for
help. Type
'\c'
to clearthe current input statement.
mysql>
|
#修改mysql超级管理root密码
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mysql> update mysql.user setpassword=PASSWORD(
'oldboy'
) where user=
'root'
and host=
'localhost'
;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
|
#修改mysql启动脚本中用户密码
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1
2
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[root@db02 ~]
# grep "pwd"/data/3306/mysql
mysql_pwd=
"oldboy"
|
#停止服务
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2
3
4
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[root@db02 ~]
# /data/3306/mysql stop
Stoping MySQL...
[1]+ Done mysqld_safe --defaults-
file
=
/data/3306/my
.cnf --skip-grant-tables&>
/dev/null
[root@db02 ~]
# netstat -lutnp |grep 3306
|
#在启动服务
|
1
2
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[root@db02 ~]
# /data/3306/mysql start
Starting MySQL...
|
#登录数据库
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8
9
10
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[root@db02 ~]
# mysql -uroot -poldboy -S/data/3306/mysql.sock
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection
id
is 1
Server version: 5.5.32-log Source distribution
Copyright (c) 2000, 2013, Oracle and
/or
itsaffiliates. All rights reserved.
Oracle is a registered trademark of OracleCorporation and
/or
its
affiliates. Other names may be trademarks oftheir respective
owners.
Type
'help;'
or
'\h'
for
help. Type
'\c'
to clearthe current input statement.
mysql>
|
#完成！
20.MySQL内中文数据乱码的原理及如何防止乱码？（可选）。
数据库服务的字符集
|
1
2
3
4
5
6
7
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|character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
|
系统字符集配置文件
|
1
2
3
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[root@db02 ~]
# cat /etc/sysconfig/i18n
LANG=
"en_US.UTF-8"
SYSFONT=
"latarcyrheb-sun16"
|
客户端软件CRT/xshell等软件字符集要用utf8
21.在把id列设置为主键，在Name字段上创建普通索引。
mysql> alter table oldboy.test add primarykey(id);
Query OK, 3 rows affected (0.01 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> desc oldboy.test;
+-------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id |int(4) | NO | PRI | 0 | |
| age |tinyint(2) | YES | |NULL | |
| name |varchar(16) | YES | | NULL | |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)
#name字段上创建普通索引
方法一：
|
1
2
3
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mysql> alter table oldboy.
test
add indexindex_name(name);
Query OK, 0 rows affected (0.02 sec)
Records: 0 Duplicates: 0 Warnings: 0
|
方法二：
|
1
|
mysql> create index index_name onoldboy.
test
(name);
|
#查看一下
|
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2
3
4
5
6
7
8
9
|
mysql> desc oldboy.
test
;
+-------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
|
id
|int(4) | NO | PRI | 0 | |
| age |tinyint(2) | YES | |NULL | |
| name | varchar(16) |YES | MUL | NULL | |
+-------+-------------+------+-----+---------+-------+
3 rows
in
set
(0.00 sec)
|
22.在字段name后插入手机号字段(shouji)，类型char(11)。
mysql> alter table oldboy.test add shoujichar(11) after name;
Query OK, 3 rows affected (0.01 sec)
Records: 3 Duplicates: 0 Warnings: 0
|
1
2
3
4
5
6
7
8
9
10
|
mysql> desc oldboy.
test
;
+--------+-------------+------+-----+---------+-------+
| Field |Type | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
|
id
|int(4) | NO | PRI | 0 | |
| age |tinyint(2) | YES | |NULL | |
| name |varchar(16) | YES | MUL | NULL| |
| shouji | char(11) | YES | | NULL | |
+--------+-------------+------+-----+---------+-------+
4 rows
in
set
(0.00 sec)
|
23.所有字段上插入2条记录（自行设定数据）
|
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
|
mysql> insert into oldboy.testvalues(4,21,
'yifeny'
,
'15511024633'
),(5,38,
'oldboy'
,
'13512569874'
);
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql>
select
* from oldboy.
test
;
+----+------+-----------+-------------+
|
id
| age | name | shouji |
+----+------+-----------+-------------+
| 1 | NULL| oldgirl | NUL |
| 2 | NULL| 老男孩 |NULL |
| 3 | NULL| etiantian | NUL |
| 4 | 21 | yifeny | 15511024633 |
| 5 | 38 |oldboy | 13512569874 |
+----+------+-----------+-------------+
5 rows
in
set
(0.00 sec)
|
24.在手机字段上对前8个字符创建普通索引。
|
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2
3
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5
6
7
8
9
10
11
12
13
|
mysql> alter table oldboy.
test
add indexindex_shouji(shouji(8));
Query OK, 0 rows affected (0.15 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> desc oldboy.
test
;
+--------+-------------+------+-----+---------+-------+
| Field |Type | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
|
id
|int(4) | NO | PRI | 0 | |
| age |tinyint(2) | YES | |NULL | |
| name | varchar(16)| YES | MUL | NULL | |
| shouji | char(11) | YES | MUL | NULL | |
+--------+-------------+
|
------+-----+---------+-------+
4 rows in set (0.00 sec)
25.查看创建的索引及索引类型等信息。
|
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5
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7
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9
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11
12
13
14
15
|
mysql> show index from oldboy.
test
\G
*************************** 1. row***************************
Table:
test
Non_unique: 0
Key_name: PRIMARY
Seq_in_index: 1
Column_name:
id
Collation: A
Cardinality: 5
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
Index_comment:
|
|
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2
3
4
5
6
7
8
9
10
11
12
13
14
|
*************************** 2. row***************************
Table:
test
Non_unique: 1
Key_name: index_name
Seq_in_index: 1
Column_name: name
Collation: A
Cardinality: 5
Sub_part: NULL
Packed: NULL
Null: YES
Index_type: BTREE
Comment:
Index_comment:
|
|
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
|
*************************** 3. row***************************
Table:
test
Non_unique: 1
Key_name: index_shouji
Seq_in_index: 1
Column_name: shouji
Collation: A
Cardinality: 5
Sub_part: 8
Packed: NULL
Null: YES
Index_type: BTREE
Comment:
Index_comment:
3 rows
in
set
(0.00 sec)
|
26.删除Name，shouji列的索引。
mysql> alter table oldboy.test drop indexindex_name;
Query OK, 0 rows affected (0.00 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> drop index index_shouji on oldboy.test;
Query OK, 0 rows affected (0.00 sec)
Records: 0 Duplicates: 0 Warnings: 0
|
1
2
3
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5
6
7
8
9
10
11
12
13
14
15
16
|
mysql> show index from oldboy.
test
\G
*************************** 1. row***************************
Table:
test
Non_unique: 0
Key_name: PRIMARY
Seq_in_index: 1
Column_name:
id
Collation: A
Cardinality: 5
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
Index_comment:
1 row
in
set
(0.00 sec)
|
27.对Name列的前6个字符以及手机列的前8个字符组建联合索引。
mysql> alter table oldboy.test add indexindex_name_shouji(name(6),shouji(8));
Query OK, 0 rows affected (0.02 sec)
Records: 0 Duplicates: 0 Warnings: 0
|
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2
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4
5
6
7
8
9
10
11
12
13
14
15
|
mysql> show index from oldboy.
test
\G
*************************** 1. row***************************
Table:
test
Non_unique: 0
Key_name: PRIMARY
Seq_in_index: 1
Column_name:
id
Collation: A
Cardinality: 5
Sub_part: NULL
Packed: NULL
Null:
Index_type: BTREE
Comment:
Index_comment:
|
|
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2
3
4
5
6
7
8
9
10
11
12
13
14
|
*************************** 2. row***************************
Table:
test
Non_unique: 1
Key_name: index_name_shouji
Seq_in_index: 1
Column_name: name
Collation: A
Cardinality: 5
Sub_part: 6
Packed: NULL
Null: YES
Index_type: BTREE
Comment:
Index_comment:
|
|
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5
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7
8
9
10
11
12
13
14
15
|
*************************** 3. row***************************
Table:
test
Non_unique: 1
Key_name: index_name_shouji
Seq_in_index: 2
Column_name: shouji
Collation: A
Cardinality: 5
Sub_part: 8
Packed: NULL
Null: YES
Index_type: BTREE
Comment:
Index_comment:
3 rows
in
set
(0.00 sec)
|
28.查询手机号以135开头的，名字为oldboy的记录（此记录要提前插入）。
|
1
2
3
4
5
6
7
|
mysql>
select
* from oldboy.
test
wherename=
'oldboy'
and shouji like
'135%'
;
+----+------+--------+-------------+
|
id
| age | name | shouji |
+----+------+--------+-------------+
| 5 | 38 | oldboy | 13512569874 |
+----+------+--------+-------------+
1 row
in
set
(0.00 sec)
|
29.查询上述语句的执行计划（是否使用联合索引等）。
mysql> explain select * from oldboy.test where name='oldboy' andshouji like '135%';
+----+-------------+-------+-------+-------------------+-------------------+---------+------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+-------+-------------------+-------------------+---------+------+------+-------------+
| 1 | SIMPLE | test | range | index_name_shouji |index_name_shouji | 32 | NULL | 1 |Using where |
+----+-------------+-------+-------+-------------------+-------------------+---------+------+------+-------------+
1 row in set (0.00 sec)
|
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11
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13
|
mysql> explain
select
* from oldboy.
test
where name=
'oldboy'
andshouji like
'135%'
\G
*************************** 1. row***************************
id
: 1
select_type: SIMPLE
table:
test
type
: range
possible_keys: index_name_shouji
key:index_name_shouji
key_len: 32
ref: NULL
rows: 1
Extra: Using where
1 row
in
set
(0.00 sec)
|
30.把test表的引擎改成MyISAM。
MySQL数据库5.1版本以前默认的引擎是MyISAM
MySQL数据库5.5版本以后默认的引擎都是InnoDB
#首先现在查看一下test表的引擎
|
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5
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8
9
10
11
12
|
mysql> show create table oldboy.
test
\G
*************************** 1. row ***************************
Table:
test
Create Table: CREATE TABLE `
test
` (
`
id
` int(4) NOT NULL DEFAULT
'0'
,
`age` tinyint(2) DEFAULTNULL,
`name` varchar(16) DEFAULTNULL,
`shouji` char(11) DEFAULTNULL,
PRIMARY KEY (`
id
`),
KEY `index_name_shouji`(`name`(6),`shouji`(8))
) ENGINE=InnoDB DEFAULT CHARSET=gbk
1 row
in
set
(0.00 sec)
|
#修改默认引擎为MyISAM
|
1
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3
4
5
6
7
8
9
10
11
12
13
14
15
16
|
mysql> alter table oldboy.
test
ENGINE=MyISAM;
Query OK, 5 rows affected (0.01 sec)
Records: 5 Duplicates: 0 Warnings: 0
mysql> show create table oldboy.
test
\G
*************************** 1. row ***************************
Table:
test
Create Table: CREATE TABLE `
test
` (
`
id
` int(4) NOT NULL DEFAULT
'0'
,
`age` tinyint(2) DEFAULTNULL,
`name` varchar(16) DEFAULTNULL,
`shouji` char(11) DEFAULTNULL,
PRIMARY KEY (`
id
`),
KEY `index_name_shouji`(`name`(6),`shouji`(8))
) ENGINE=MyISAM DEFAULT CHARSET=gbk
1 row
in
set
(0.00 sec)
|
在这里有些代码字体颜色不了高亮显示，这是一个忧伤的故事！如果有人知道麻烦指点一下，真的很难受！