15個 MySQL 基礎面試題，DBA 們準備好了嗎？

問題1：你如何確定 MySQL 是否處於運行狀態？

答案： Debian 上運行命令 service mysql status，在RedHat 上運行命令 service mysqld status。然後看看輸出即可。

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.

問題2：如何開啟或停止 MySQL 服務？

答案：運行命令 service mysqld start 開啟服務；運行命令 service mysqld stop 停止服務。

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..

問題3：如何通過 Shell 登入 MySQL？

答案：運行命令 mysql -u root -p

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>

問題4：如何列出所有資料庫？

答案：運行命令 show databases;

mysql> show databases; 
+--------------------+ 
| Database           | 
+--------------------+ 
| information_schema | 
| a1                 | 
| cloud              | 
| mysql              | 
| phpmyadmin         | 
| playsms            | 
| sisso              | 
| test               | 
| ukolovnik          | 
| wordpress          | 
+--------------------+ 
10 rows in set (0.14 sec)

問題5： 如何切換到某個資料庫並在上面工作？

答案：運行命令 use database_name; 進入名為 database_name 的資料庫。

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>

問題6：如何列出某個資料庫內所有表？

答案：在當前資料庫運行命令 show tables;

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)

問題7：如何獲取表內所有 Field 對象的名稱和類型？

答案：運行命令 describe table_name;

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)

問題8：如何刪除表？

答案：運行命令 drop table table_name;

mysql> drop table lookup; 

Query OK, 0 rows affected (0.00 sec)

問題9：如何刪除資料庫？

答案：運行命令 drop database database-name;

mysql> drop database a1; 

Query OK, 11 rows affected (0.07 sec)

問題10：如何查看錶內所有數據？

答案：運行命令 *select from table_name;**

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)

問題11：如何從表（比如 oc_users ）中獲取一個 field 對象（比如 uid）的所有數據？

答案：運行命令 select uid from oc_users;

mysql> select uid from oc_users; 
+-----+ 
| uid | 
+-----+ 
| avi | 
+-----+ 
1 row in set (0.03 sec)

問題12：假設你有一個名為 『xyz』 的表，它存在多個欄位，如 『createtime』 和 『engine』。名為 engine 的欄位由 『Memoty』 和 『MyIsam』 兩種數值組成。如何只列出 『createtime』 和 『engine』 這兩列並且 engine 的值為 『MyIsam』？

答案：運行命令 select create_time, engine from xyz where engine = 」MyIsam」;

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)

問題13：如何列出表 『xrt』 內 name 域值為 『tecmint』，web_address 域值為 『tecmint.com』 的所有數據？

答案：運行命令 *select from xrt where name = 「tecmint」 and web_address = 「tecmint.com」;**

mysql> select  * from xrt where name = "tecmint" and web_address = 「tecmint.com」;
+---------------+---------------------+---------------+ 
| Id                  | name                   | web_address | 
+---------------+---------------------+----------------+ 
| 13                 |  tecmint               | tecmint.com  |
+---------------+---------------------+----------------+ 
| 41                 |  tecmint               | tecmint.com  |
+---------------+---------------------+----------------+

問題14：如何列出表 『xrt』 內 name 域值不為 『tecmint』，web_address 域值為 『tecmint.com』 的所有數據？

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

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

+---------------+---------------------+---------------+ 
| Id            | name                | web_address   | 
+---------------+---------------------+----------------+ 
| 1173          |  tecmint            | tecmint.com   |
+---------------+---------------------+----------------+

問題15：如何知道表內行數？

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

mysql> select count(*) from Tables; 

+----------+ 
| count(*) | 
+----------+ 
|      282 | 
+----------+ 
1 row in set (0.01 sec)

以上是文章的全部內容。這篇『Linux 面試題』對您有任何幫助嗎？別忘了在下面留言，寫出您的寶貴意見。

via: http://www.tecmint.com/basic-mysql-interview-questions-for-database-administrators/

譯者：bazz2 校對：Caroline

本文由 LCTT 原創翻譯，Linux中國 榮譽推出

本文轉載來自 Linux 中國: https://github.com/Linux-CN/archive