Overview
This Post is to give you the basic commands in mysql so you can do basic administration.This is based on mysql installed on a linux host
How to start/Stop/Restart MySQL
service mysql start
service mysql stop
service mysql restart
How to check MySQL instance status
mysql -uroot -pyour_password -e STATUS
-------------- mysql Ver 14.14 Distrib 5.5.27, for Linux (x86_64) using EditLine wrapper Connection id: 70 Current database: Current user: root@localhost SSL: Not in use Current pager: stdout Using outfile: '' Using delimiter: ; Server version: 5.5.27-enterprise-commercial-advanced-log MySQL Enterprise Server - Advanced Edition (Commercial) Protocol version: 10 Connection: Localhost via UNIX socket Server characterset: latin1 Db characterset: latin1 Client characterset: utf8 Conn. characterset: utf8 UNIX socket: /var/lib/mysql/mysql.sock Uptime: 14 hours 47 min 44 sec Threads: 1 Questions: 546080 Slow queries: 0 Opens: 19103 Flush tables: 27 Open tables: 2079 Queries per second avg: 10.252 --------------
How to see the MySQL processes in linux
ps -ef | grep -i mysql
root 16111 1 0 08:55 ? 00:00:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --pid-file=/var/lib/mysql/prodmysql02.pid mysql 16540 16111 1 08:55 ? 00:12:45 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --user=mysql --log-error=/var/lib/mysql/prodmysql02.err --pid-file=/var/lib/mysql/prodmysql02.pid --socket=/var/lib/mysql/mysql.sock
How to connect to the instance mysql
mysql -uusername -pyour_password
How to create a database
The simpliest way iscreate database my_database;
or to avoid error message if the database already exist
create database if not exists my_database;
How to drop a database
Just a warning, when dropping a database, the system won't ask you to confirm if you want to drop it.drop database my_database;
How to connect or change database
use rcinetor
use rcinet;
How to list the databases in MySQL
show databases;
+--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | test | +--------------------+ 10 rows in set (0.01 sec)
How to check the size of the databases
This is a select that was given to me by one of my friend when I was looking for this information. I kept it and scripts it.SELECT table_schema "db_name",
sum(data_length+index_length) /1024/1024 "db_size in Mb"
FROM information_schema.tables
GROUP BY 1;
+--------------------+---------------+ | db_name | db_size in Mb | +--------------------+---------------+ | information_schema | 0.00878906 | | mysql | 0.62183380 | | performance_schema | 0.00000000 | +--------------------+---------------+ 9 rows in set (10.94 sec)
How to create a table in MySQL
CREATE TABLE my_table (
mycol1 INT(5) NOT NULL DEFAULT 0,
mycol2 CHAR(100) DEFAULT NULL,
PRIMARY KEY (mycol1)
);
How to show the tables in a database
show tables;
+-------------------------+ | Tables_in_xmas_card2012 | +-------------------------+ | my_table | +-------------------------+ 1 row in set (0.00 sec)
How to create a user in MySQL
create user account1 identified by 'your_password';
grant all privileges on *.* to account1;
How to list the users in mysql
select user,host from mysql.user;
+-------------+--------------------------------+ | user | host | +-------------+--------------------------------+ | root | % | | root | 127.0.0.1 | | dbaadmin | localhost | | root | localhost | +-------------+--------------------------------+ 15 rows in set (0.02 sec)
How to show the status of a Master or Slave/Replica in MySQL
show master status\G This is on a master instance
*************************** 1. row ***************************
File: log-bin.000078
Position: 64150203
Binlog_Do_DB:
Binlog_Ignore_DB:
1 row in set (0.00 sec)
or
show slave status\G This is on a Slave/Replica instance
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: xxx.xxx.xxx.xxx
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: log-bin.000056
Read_Master_Log_Pos: 986876833
Relay_Log_File: mysql_relay-bin.000130
Relay_Log_Pos: 64787846
Relay_Master_Log_File: log-bin.000056
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 986876833
Relay_Log_Space: 64972302
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 123
1 row in set (0.00 sec)
How to flush the data to disk and set the database in read only
flush tables with read lock;
How to remove the read only on a database
unlock tables;
How to check and repair a database
mysqlcheck -c your_database -uroot -pyour_password --auto-repair
Character set in MySQL
Character sets are mainly used to tell MySQL what to store in MySQL dependng of the language. Character set can be defined at- the server level
- the database level
- the table level
- the column level
show character set;
+----------+-----------------------------+---------------------+--------+ | Charset | Description | Default collation | Maxlen | +----------+-----------------------------+---------------------+--------+ | big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 | | dec8 | DEC West European | dec8_swedish_ci | 1 | | cp850 | DOS West European | cp850_general_ci | 1 | | hp8 | HP West European | hp8_english_ci | 1 | | koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 | | latin1 | cp1252 West European | latin1_swedish_ci | 1 | | latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 | | swe7 | 7bit Swedish | swe7_swedish_ci | 1 | | ascii | US ASCII | ascii_general_ci | 1 | | ujis | EUC-JP Japanese | ujis_japanese_ci | 3 | | sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 | | hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 | | tis620 | TIS620 Thai | tis620_thai_ci | 1 | | euckr | EUC-KR Korean | euckr_korean_ci | 2 | | koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 | | gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 | | greek | ISO 8859-7 Greek | greek_general_ci | 1 | | cp1250 | Windows Central European | cp1250_general_ci | 1 | | gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 | | latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 | | armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 | | utf8 | UTF-8 Unicode | utf8_general_ci | 3 | | ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 | | cp866 | DOS Russian | cp866_general_ci | 1 | | keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 | | macce | Mac Central European | macce_general_ci | 1 | | macroman | Mac West European | macroman_general_ci | 1 | | cp852 | DOS Central European | cp852_general_ci | 1 | | latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 | | utf8mb4 | UTF-8 Unicode | utf8mb4_general_ci | 4 | | cp1251 | Windows Cyrillic | cp1251_general_ci | 1 | | utf16 | UTF-16 Unicode | utf16_general_ci | 4 | | cp1256 | Windows Arabic | cp1256_general_ci | 1 | | cp1257 | Windows Baltic | cp1257_general_ci | 1 | | utf32 | UTF-32 Unicode | utf32_general_ci | 4 | | binary | Binary pseudo charset | binary | 1 | | geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 | | cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 | | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 | +----------+-----------------------------+---------------------+--------+ 39 rows in set (0.03 sec)
Collation in MySQL
Collation in MySQL is used for how the data is sort. Each character has a position in the ordering process.show character set;
+----------+-----------------------------+---------------------+--------+ | Charset | Description | Default collation | Maxlen | +----------+-----------------------------+---------------------+--------+ | big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 | | dec8 | DEC West European | dec8_swedish_ci | 1 | | cp850 | DOS West European | cp850_general_ci | 1 | | hp8 | HP West European | hp8_english_ci | 1 | | koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 | | latin1 | cp1252 West European | latin1_swedish_ci | 1 | | latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 | | swe7 | 7bit Swedish | swe7_swedish_ci | 1 | | ascii | US ASCII | ascii_general_ci | 1 | | ujis | EUC-JP Japanese | ujis_japanese_ci | 3 | | sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 | | hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 | | tis620 | TIS620 Thai | tis620_thai_ci | 1 | | euckr | EUC-KR Korean | euckr_korean_ci | 2 | | koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 | | gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 | | greek | ISO 8859-7 Greek | greek_general_ci | 1 | | cp1250 | Windows Central European | cp1250_general_ci | 1 | | gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 | | latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 | | armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 | | utf8 | UTF-8 Unicode | utf8_general_ci | 3 | | ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 | | cp866 | DOS Russian | cp866_general_ci | 1 | | keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 | | macce | Mac Central European | macce_general_ci | 1 | | macroman | Mac West European | macroman_general_ci | 1 | | cp852 | DOS Central European | cp852_general_ci | 1 | | latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 | | utf8mb4 | UTF-8 Unicode | utf8mb4_general_ci | 4 | | cp1251 | Windows Cyrillic | cp1251_general_ci | 1 | | utf16 | UTF-16 Unicode | utf16_general_ci | 4 | | cp1256 | Windows Arabic | cp1256_general_ci | 1 | | cp1257 | Windows Baltic | cp1257_general_ci | 1 | | utf32 | UTF-32 Unicode | utf32_general_ci | 4 | | binary | Binary pseudo charset | binary | 1 | | geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 | | cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 | | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 | +----------+-----------------------------+---------------------+--------+ 39 rows in set (0.01 sec)
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