TranslateProject/translated/15 Basic MySQL Interview Questions for Database Administrators.md

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15个 MySQL 基础面试题DBA 准备好了吗?
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此前我们已经有发表过[Linux 面试基础问答]共3篇文章获得读者的好评同时我们得到反馈有些读者希望这种交互式学习方法能够做得更加灵活。心动不如行动我们这就为您奉上**15道 MySQL 面试题**
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![](http://www.tecmint.com/wp-content/uploads/2013/12/Mysql-Interview-Questions.png)
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### 问题1你如何确定 MySQL 是否处于运行状态? ###
> **答案** Debian 上运行命令 **service mysql status;**RedHat 上运行命令 **service mysqld status;**。然后看看输出即可。
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root@localhost:/home/avi# service mysql status
/usr/bin/mysqladmin Ver 8.42 Distrib 5.1.72, for debian-linux-gnu on i486
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Server version 5.1.72-2
Protocol version 10
Connection Localhost via UNIX socket
UNIX socket /var/run/mysqld/mysqld.sock
Uptime: 1 hour 22 min 49 sec
Threads: 1 Questions: 112138 Slow queries: 1 Opens: 1485 Flush tables: 1 Open tables: 64 Queries per second avg: 22.567.
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### 问题2如何关闭或开启 MySQL 服务? ###
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> **答案**:运行命令 **service mysqld start;** 开启服务;运行命令 **service mysqld stop** 停止服务。
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root@localhost:/home/avi# service mysql stop
Stopping MySQL database server: mysqld.
root@localhost:/home/avi# service mysql start
Starting MySQL database server: mysqld.
Checking for corrupt, not cleanly closed and upgrade needing tables..
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### 问题3如何通过 Shell 登入 MySQL ###
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> **答案**:运行命令 **mysql -u root -p;**
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root@localhost:/home/avi# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 207
Server version: 5.1.72-2 (Debian)
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
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>
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### 问题4如何列出所有数据库 ###
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> **答案**:运行命令 **show databases;**
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mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| a1 |
| cloud |
| mysql |
| phpmyadmin |
| playsms |
| sisso |
| test |
| ukolovnik |
| wordpress |
+--------------------+
10 rows in set (0.14 sec)
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### 问题5 如何切换到某个数据库并在上面工作? ###
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> **答案**:运行命令 **use database_name;** 进入名为 database_name 的数据库。
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mysql> use cloud;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql>
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### 问题6如何列出某个数据库内所有表 ###
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> **答案**:在当前数据库运行命令 **show tables;**
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mysql> show tables;
+----------------------------+
| Tables_in_cloud |
+----------------------------+
| oc_appconfig |
| oc_calendar_calendars |
| oc_calendar_objects |
| oc_calendar_repeat |
| oc_calendar_share_calendar |
| oc_calendar_share_event |
| oc_contacts_addressbooks |
| oc_contacts_cards |
| oc_fscache |
| oc_gallery_sharing |
+----------------------------+
10 rows in set (0.00 sec)
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### 问题7如何获取表内所有 Field 对象的名称和类型? ###
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> **答案**:运行命令 **describe table_name;** 查看名为 table_name 的表。
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mysql> describe oc_users;
+----------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+-------+
| uid | varchar(64) | NO | PRI | | |
| password | varchar(255) | NO | | | |
+----------+--------------+------+-----+---------+-------+
2 rows in set (0.00 sec)
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### 问题8如何删除表 ###
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> **答案**:运行命令 **drop table table_name;**
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mysql> drop table lookup;
Query OK, 0 rows affected (0.00 sec)
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### 问题9如何删除数据库 ###
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> **答案**:运行命令 **drop database database-name;**
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mysql> drop database a1;
Query OK, 11 rows affected (0.07 sec)
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### 问题10如何查看表内所有数据 ###
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> **答案**:运行命令 **select * from table_name;**
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mysql> select * from engines;
+------------+---------+----------------------------------------------------------------+--------------+------+------------+
| ENGINE | SUPPORT | COMMENT | TRANSACTIONS | XA | SAVEPOINTS |
+------------+---------+----------------------------------------------------------------+--------------+------+------------+
| InnoDB | YES | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO |
| CSV | YES | CSV storage engine | NO | NO | NO |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO |
| FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| MyISAM | DEFAULT | Default engine as of MySQL 3.23 with great performance | NO | NO | NO |
+------------+---------+----------------------------------------------------------------+--------------+------+------------+
8 rows in set (0.00 sec)
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### 问题11如何从 oc_users 这个表获取一个 field 对象(比如 uid的所有数据 ###
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> **答案**:运行命令 **select uid from oc_users;**。
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mysql> select uid from oc_users;
+-----+
| uid |
+-----+
| avi |
+-----+
1 row in set (0.03 sec)
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### 问题12假设你有一个表名为 xyz存在多个 field如 create_time 和 engine。名为 engine 的 field 由 MemotyMyIsam 两种数值组成。如何只列出 create_time 和 engine 这两列并且 engine 的值为 MyIsam ###
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> **答案**:运行命令 **select create_time, engine from xyz where engine = ”MyIsam”;**
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mysql> select create_time, engine from xyz where engine="MyIsam";
+---------------------+--------+
| create_time | engine |
+---------------------+--------+
| 2013-12-15 13:43:27 | MyISAM |
| 2013-12-15 13:43:27 | MyISAM |
| 2013-12-15 13:43:27 | MyISAM |
| 2013-12-15 13:43:27 | MyISAM |
| 2013-12-15 13:43:27 | MyISAM |
| 2013-12-15 13:43:27 | MyISAM |
| 2013-12-15 13:43:27 | MyISAM |
| 2013-12-15 13:43:27 | MyISAM |
| 2013-10-23 14:56:38 | MyISAM |
| 2013-10-23 14:56:38 | MyISAM |
| 2013-10-23 14:56:38 | MyISAM |
| 2013-10-23 14:56:38 | MyISAM |
| 2013-10-23 14:56:38 | MyISAM |
| 2013-10-23 14:56:38 | MyISAM |
| 2013-10-23 14:56:38 | MyISAM |
+---------------------+--------+
132 rows in set (0.29 sec)
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### 问题13如何列出表 xrt 内 name 域值为 tecmintweb_address 域值为 tecmint.com 的所有数据? ###
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> **答案**:运行命令 **select * from xrt where name = “tecmint” and web_address = “tecmint.com”;**
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mysql> select * from xrt where name = "tecmint" and web_address = “tecmint.com”;
+---------------+---------------------+---------------+
| Id | name | web_address |
+---------------+---------------------+----------------+
| 13 | tecmint | tecmint.com |
+---------------+---------------------+----------------+
| 41 | tecmint | tecmint.com |
+---------------+---------------------+----------------+
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### 问题14如何列出表 xrt 内 name 域值_不_为 tecmintweb_address 域值为 tecmint.com 的所有数据? ###
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> **答案**:运行命令 **select * from xrt where name != "tecmint" and web_address = "tecmint.com";**
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mysql> select * from xrt where name != ”tecmint” and web_address = ”tecmint.com”;
+---------------+---------------------+---------------+
| Id | name | web_address |
+---------------+---------------------+----------------+
| 1173 | tecmint | tecmint.com |
+---------------+---------------------+----------------+
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### 问题15你需要知道表内行数这个该怎么做
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> **答案**:运行命令 **select count(*) from table_name;**
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mysql> select count(*) from Tables;
+----------+
| count(*) |
+----------+
| 282 |
+----------+
1 row in set (0.01 sec)
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