15个 MySQL 基础面试题，DBA 们准备好了吗？

此前我们已经有发表过Linux 面试基础问答之一、二和三共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个 MySQL 面试题

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，在RedHat 上运行命令 service mysqld status。然后看看输出即可。



  1. root@localhost:/home/avi# service mysql status
    2. 

    3. 

  3. /usr/bin/mysqladmin  Ver 8.42 Distrib 5.1.72, for debian-linux-gnu on i486
    4. 

  4. Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
    5. 

    6. 

  6. Oracle is a registered trademark of Oracle Corporation and/or its
    7. 

  7. affiliates. Other names may be trademarks of their respective
    8. 

  8. owners.
    9. 

    10. 

  10. Server version 5.1.72-2
    11. 

  11. Protocol version 10
    12. 

  12. Connection Localhost via UNIX socket
    13. 

  13. UNIX socket /var/run/mysqld/mysqld.sock
    14. 

  14. Uptime: 1 hour 22 min 49 sec
    15. 

    16. 

  16. Threads: 1  Questions: 112138  Slow queries: 1  Opens: 1485  Flush tables: 1  Open tables: 64  Queries per second avg: 22.567.
    17. 



问题2：如何开启或停止 MySQL 服务？




答案：运行命令 service mysqld start 开启服务；运行命令 service mysqld stop 停止服务。






  1. root@localhost:/home/avi# service mysql stop
    2. 

    3. 

  3. Stopping MySQL database server: mysqld.
    4. 

    5. 

  5. root@localhost:/home/avi# service mysql start
    6. 

    7. 

  7. Starting MySQL database server: mysqld.
    8. 

    9. 

  9. Checking for corrupt, not cleanly closed and upgrade needing tables..
    10. 



问题3：如何通过 Shell 登入 MySQL？




答案：运行命令 mysql -u root -p






  1. root@localhost:/home/avi# mysql -u root -p 
    2. 

  2. Enter password: 
    3. 

  3. Welcome to the MySQL monitor.  Commands end with ; or g. 
    4. 

  4. Your MySQL connection id is 207 
    5. 

  5. Server version: 5.1.72-2 (Debian) 
    6. 

    7. 

  7. Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved. 
    8. 

    9. 

  9. Oracle is a registered trademark of Oracle Corporation and/or its 
    10. 

  10. affiliates. Other names may be trademarks of their respective 
    11. 

  11. owners. 
    12. 

    13. 

  13. Type 'help;' or 'h' for help. Type 'c' to clear the current input statement. 
    14. 

    15. 

  15. mysql>
    16. 



问题4：如何列出所有数据库？




答案：运行命令 show databases;






  1. mysql> show databases; 
    2. 

  2. +--------------------+ 
    3. 

  3. | Database           | 
    4. 

  4. +--------------------+ 
    5. 

  5. | information_schema | 
    6. 

  6. | a1                 | 
    7. 

  7. | cloud              | 
    8. 

  8. | mysql              | 
    9. 

  9. | phpmyadmin         | 
    10. 

  10. | playsms            | 
    11. 

  11. | sisso              | 
    12. 

  12. | test               | 
    13. 

  13. | ukolovnik          | 
    14. 

  14. | wordpress          | 
    15. 

  15. +--------------------+ 
    16. 

  16. 10 rows in set (0.14 sec)
    17. 



问题5： 如何切换到某个数据库并在上面工作？




答案：运行命令 use database_name; 进入名为 database_name 的数据库。






  1. mysql> use cloud; 
    2. 

  2. Reading table information for completion of table and column names 
    3. 

  3. You can turn off this feature to get a quicker startup with -A 
    4. 

    5. 

  5. Database changed 
    6. 

  6. mysql>
    7. 



问题6：如何列出某个数据库内所有表？




答案：在当前数据库运行命令 show tables;






  1. mysql> show tables; 
    2. 

  2. +----------------------------+ 
    3. 

  3. | Tables_in_cloud            | 
    4. 

  4. +----------------------------+ 
    5. 

  5. | oc_appconfig               | 
    6. 

  6. | oc_calendar_calendars      | 
    7. 

  7. | oc_calendar_objects        | 
    8. 

  8. | oc_calendar_repeat         | 
    9. 

  9. | oc_calendar_share_calendar | 
    10. 

  10. | oc_calendar_share_event    | 
    11. 

  11. | oc_contacts_addressbooks   | 
    12. 

  12. | oc_contacts_cards          | 
    13. 

  13. | oc_fscache                 | 
    14. 

  14. | oc_gallery_sharing         | 
    15. 

  15. +----------------------------+ 
    16. 

  16. 10 rows in set (0.00 sec)
    17. 



问题7：如何获取表内所有 Field 对象的名称和类型？




答案：运行命令 describe table_name;






  1. mysql> describe oc_users; 
    2. 

  2. +----------+--------------+------+-----+---------+-------+ 
    3. 

  3. | Field    | Type         | Null | Key | Default | Extra | 
    4. 

  4. +----------+--------------+------+-----+---------+-------+ 
    5. 

  5. | uid      | varchar(64)  | NO   | PRI |         |       | 
    6. 

  6. | password | varchar(255) | NO   |     |         |       | 
    7. 

  7. +----------+--------------+------+-----+---------+-------+ 
    8. 

  8. 2 rows in set (0.00 sec)
    9. 



问题8：如何删除表？




答案：运行命令 drop table table_name;






  1. mysql> drop table lookup; 
    2. 

    3. 

  3. Query OK, 0 rows affected (0.00 sec)
    4. 



问题9：如何删除数据库？




答案：运行命令 drop database database-name;






  1. mysql> drop database a1; 
    2. 

    3. 

  3. Query OK, 11 rows affected (0.07 sec)
    4. 



问题10：如何查看表内所有数据？




答案：运行命令 select * from table_name;






  1. mysql> select * from engines; 
    2. 

  2. +------------+---------+----------------------------------------------------------------+--------------+------+------------+ 
    3. 

  3. | ENGINE     | SUPPORT | COMMENT                                                        | TRANSACTIONS | XA   | SAVEPOINTS | 
    4. 

  4. +------------+---------+----------------------------------------------------------------+--------------+------+------------+ 
    5. 

  5. | InnoDB     | YES     | Supports transactions, row-level locking, and foreign keys     | YES          | YES  | YES        | 
    6. 

  6. | MRG_MYISAM | YES     | Collection of identical MyISAM tables                          | NO           | NO   | NO         | 
    7. 

  7. | BLACKHOLE  | YES     | /dev/null storage engine (anything you write to it disappears) | NO           | NO   | NO         | 
    8. 

  8. | CSV        | YES     | CSV storage engine                                             | NO           | NO   | NO         | 
    9. 

  9. | MEMORY     | YES     | Hash based, stored in memory, useful for temporary tables      | NO           | NO   | NO         | 
    10. 

  10. | FEDERATED  | NO      | Federated MySQL storage engine                                 | NULL         | NULL | NULL       | 
    11. 

  11. | ARCHIVE    | YES     | Archive storage engine                                         | NO           | NO   | NO         | 
    12. 

  12. | MyISAM     | DEFAULT | Default engine as of MySQL 3.23 with great performance         | NO           | NO   | NO         | 
    13. 

  13. +------------+---------+----------------------------------------------------------------+--------------+------+------------+ 
    14. 

  14. 8 rows in set (0.00 sec)
    15. 



问题11：如何从表（比如 oc_users ）中获取一个 field 对象（比如 uid）的所有数据？




答案：运行命令 select uid from oc_users;






  1. mysql> select uid from oc_users; 
    2. 

  2. +-----+ 
    3. 

  3. | uid | 
    4. 

  4. +-----+ 
    5. 

  5. | avi | 
    6. 

  6. +-----+ 
    7. 

  7. 1 row in set (0.03 sec)
    8. 

问题12：假设你有一个名为 ‘xyz’ 的表，它存在多个字段，如 ‘createtime’ 和 ‘engine’。名为 engine 的字段由 ‘Memoty’ 和 ‘MyIsam’ 两种数值组成。如何只列出 ‘createtime’ 和 ‘engine’ 这两列并且 engine 的值为 ‘MyIsam’？




答案：运行命令 select create_time, engine from xyz where engine = ”MyIsam”;






  1. mysql> select create_time, engine from xyz where engine="MyIsam";
    2. 

    3. 

  3. +---------------------+--------+ 
    4. 

  4. | create_time         | engine | 
    5. 

  5. +---------------------+--------+ 
    6. 

  6. | 2013-12-15 13:43:27 | MyISAM | 
    7. 

  7. | 2013-12-15 13:43:27 | MyISAM | 
    8. 

  8. | 2013-12-15 13:43:27 | MyISAM | 
    9. 

  9. | 2013-12-15 13:43:27 | MyISAM | 
    10. 

  10. | 2013-12-15 13:43:27 | MyISAM | 
    11. 

  11. | 2013-12-15 13:43:27 | MyISAM | 
    12. 

  12. | 2013-12-15 13:43:27 | MyISAM | 
    13. 

  13. | 2013-12-15 13:43:27 | MyISAM | 
    14. 

  14. | 2013-10-23 14:56:38 | MyISAM | 
    15. 

  15. | 2013-10-23 14:56:38 | MyISAM | 
    16. 

  16. | 2013-10-23 14:56:38 | MyISAM | 
    17. 

  17. | 2013-10-23 14:56:38 | MyISAM | 
    18. 

  18. | 2013-10-23 14:56:38 | MyISAM | 
    19. 

  19. | 2013-10-23 14:56:38 | MyISAM | 
    20. 

  20. | 2013-10-23 14:56:38 | MyISAM | 
    21. 

  21. +---------------------+--------+ 
    22. 

  22. 132 rows in set (0.29 sec)
    23. 

问题13：如何列出表 ‘xrt’ 内 name 域值为 ‘tecmint’，web_address 域值为 ‘tecmint.com’ 的所有数据？




答案：运行命令 select * from xrt where name = “tecmint” and web_address = “tecmint.com”;






  1. mysql> select  * from xrt where name = "tecmint" and web_address = “tecmint.com”;
    2. 

  2. +---------------+---------------------+---------------+ 
    3. 

  3. | Id                  | name                   | web_address | 
    4. 

  4. +---------------+---------------------+----------------+ 
    5. 

  5. | 13                 |  tecmint               | tecmint.com  |
    6. 

  6. +---------------+---------------------+----------------+ 
    7. 

  7. | 41                 |  tecmint               | tecmint.com  |
    8. 

  8. +---------------+---------------------+----------------+
    9. 

问题14：如何列出表 ‘xrt’ 内 name 域值不为 ‘tecmint’，web_address 域值为 ‘tecmint.com’ 的所有数据？




答案：运行命令 select * from xrt where name != "tecmint" and web_address = "tecmint.com";






  1. mysql> select * from xrt where name != ”tecmint” and web_address = ”tecmint.com”;
    2. 

    3. 

  3. +---------------+---------------------+---------------+ 
    4. 

  4. | Id            | name                | web_address   | 
    5. 

  5. +---------------+---------------------+----------------+ 
    6. 

  6. | 1173          |  tecmint            | tecmint.com   |
    7. 

  7. +---------------+---------------------+----------------+
    8. 



问题15：如何知道表内行数？




答案：运行命令 select count(*) from table_name;






  1. mysql> select count(*) from Tables; 
    2. 

    3. 

  3. +----------+ 
    4. 

  4. | count(*) | 
    5. 

  5. +----------+ 
    6. 

  6. |      282 | 
    7. 

  7. +----------+ 
    8. 

  8. 1 row in set (0.01 sec)
    9. 

以上是文章的全部内容。这篇‘Linux 面试题’对您有任何帮助吗？别忘了在下面留言，写出您的宝贵意见。


原文发布时间为：2014-01-05


本文来自云栖社区合作伙伴“Linux中国”


        
        
                
    
                                    


        

	      

	    

	  

	  

	    
      
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          原文地址：https://www.cnblogs.com/twodog/p/12140712.html