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。
版权声明：余连辉
本系列文档为《老男孩 Linux 运维实战培训中心》内部教学用教案，只允许 VIP 学员 个人使用，为保护大家的学习利益，禁止私自传播，违者将取消 VIP 学员资格。严重者我们将法律起诉。如果你已经参加本培训，即视为你已无条件接受上述内容说明！
联系方式：
意见投诉信箱:oldboy521@gmail.com 网站运维交流群：114580181 246054962 45039636 37081784
==========================================
老男孩linux 实训联系方式
咨询：QQ:70271111 41117397 41117483 80042789 电话：1860033834018911718229 网站地址：http://www.etiantian.org http://bbs.etiantian.org blog
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。
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。
#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)
3.创建GBK字符集的数据库oldboy，并查看已建库的完整语句。
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>
#查看已建库的完整语句
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。
mysql>grant all on oldboy.* to oldboy@‘localhost‘ identified by ‘123‘; QueryOK, 0 rows affected (0.00 sec)
5.查看创建的用户oldboy拥有哪些权限。
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。
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)
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。
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)
#查看表结构：方法一
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)
#查看表结构：方法二
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)
#查看表结构sql语句
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)
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。
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)
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
mysql> select * from test; +------+-----------+ | id |name | +------+-----------+ | 1 |oldboy | | 2 | 老男孩 | | 3 | etiantian | +------+-----------+ 3 rows in set (0.00 sec)
（2）查询名字为oldboy的记录
mysql> select * from test where name=‘oldboy‘; +------+--------+ | id | name | +------+--------+ | 1 |oldboy | +------+--------+ 1 row in set (0.01 sec)
（3）查询id大于1的记录
mysql> select * from test where id>1; +------+-----------+ | id |name | +------+-----------+ | 2 | 老男孩 | | 3 |etiantian | +------+-----------+ 2 rows in set (0.00 sec)
12.把数据id等于1的名字oldboy更改为oldgirl。
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)
13.在字段name前插入age字段，类型tinyint(2)。
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)
14.备份oldboy库及MySQL库。
退出mysql数据库在命令行输入
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
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
mysql> delete from test;
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
mysql> truncate table test; Query OK, 0 rows affected (0.00 sec)
##查看结果
mysql> select * from test; Empty set (0.00 sec)
16.删除表test和oldboy数据库并查看
#删除表test
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)
#删除数据库oldboy
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)
##查看结果
mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | +--------------------+ 3 rows in set (0.00 sec)
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
mysql -uroot -poldboy123 -S /data/3306/mysql.sock</opt/bak.sql
#登录数据库并查看结果
mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | oldboy | | performance_schema | +--------------------+ 4 rows in set (0.00 sec)
#查看test表的数据
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
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)
###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
mysql> set global character_set_database = gbk; mysql> quit；
[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)
##现在把字符集修改成utf8会了吗？
操作一下吧-_-!!!
mysql> set global character_set_database = utf8; Query OK, 0 rows affected (0.00 sec) mysql> quit; Bye
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
[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
#杀死进程pid号
[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
[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
[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
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
[root@db02 ~]# grep "pwd"/data/3306/mysql mysql_pwd="oldboy"
#停止服务
[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
[root@db02 ~]# /data/3306/mysql start Starting MySQL...
#登录数据库
[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
|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
[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：
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：
mysql> create index index_name onoldboy.test(name);
#查看一下
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
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）
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。
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。
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:
*************************** 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:
*************************** 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
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
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:
*************************** 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:
*************************** 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）。
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)
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
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
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！
本文出自 “Linux高级运维之路” 博客，请务必保留此出处http://yulianhui.blog.51cto.com/10829691/1726921
原文地址：http://yulianhui.blog.51cto.com/10829691/1726921
