Editing MySQL commands


=== Preparation ===
install MySQL database client apps contains {{kbd | key=mysql}} & {{kbd | key=mysqldump}} commands
* {{Linux}}: 
* {{Win}}: Install (1) [https://www.cygwin.com/ Cygwin], (2) search mysql & install MySQL database clients apps package
* {{Mac}}: Install [https://www.apachefriends.org/zh_tw/download.html XAMPP]. Path of {{kbd | key=mysql}} executable file is: /Applications/xampp/xamppfiles/bin/mysql

(optional) install the [http://www.ivarch.com/programs/pv.shtml Pipe Viewer] (pv) package
* {{Linux}}: 
*# [http://www.tecmint.com/enable-rpmforge-repository/ How to Enable RPMForge Repository in RHEL/CentOS 7.x/6.x/5.x/4.x]
*# (1){{kbd | key =yum install pv}} for RHEL / CentOS / SL / Fedora Linux<ref>[http://www.cyberciti.biz/open-source/command-line-hacks/pv-command-examples/ Linux / Unix pv Command: Monitor Progress of Data Sent Via a Pipe]</ref>;  (2) {{kbd | key =apt-get install pv}} for Debian / Ubuntu<ref>[http://www.ivarch.com/programs/pv.shtml ivarch.com: Pipe Viewer]</ref>; 
* {{Win}}: Install (1) [https://www.cygwin.com/ Cygwin], (2) search pv & install pv package
* {{Mac}}: Install (1) {{kbd | key =brew install pv}} to get the latest version of pv package<ref>[http://ashleyangell.com/2013/11/pipe-viewer-pv-in-mac-osx/ Pipe Viewer (pv) in Mac OSX]</ref> and (2) MySQL database clients from [https://www.apachefriends.org/zh_tw/download.html XAMPP]. Path of mysql is: /Applications/xampp/xamppfiles/bin/mysql

create the db user
# create the db user
# grant the minimum permission: {{kbd | key=SELECT}}, {{kbd | key=LOCK TABLES}} to the db user. SQL query: {{kbd | key=<nowiki>GRANT SELECT, LOCK TABLES ON `DATA\_BASE\_NAME`.* TO 'dbuser'@'localhost';</nowiki>}}<ref>[http://serverfault.com/questions/22712/minimum-permissions-for-a-user-to-perform-a-mysqldump security - Minimum permissions for a user to perform a mysqldump? - Server Fault]</ref>
# the db user will be able to execute the mysqldump command

=== Exporting data of database/table  into MySql sql file ===
==== Exporting entire data ====
'''method1''': {{Gd}} export the compressed *.sql file (especially for BIG sql file). It will show a progress bar and estimated time to complete the mysqldump<ref>[http://dba.stackexchange.com/questions/17367/how-can-i-monitor-the-progress-of-an-import-of-a-large-sql-file mysql - How can I monitor the progress of an import of a large .sql file? - Database Administrators Stack Exchange]</ref><ref>[https://dev.mysql.com/doc/refman/5.1/en/mysqldump.html MySQL :: MySQL 5.1 Reference Manual :: 4.5.4 mysqldump — A Database Backup Program]</ref><ref>[http://stackoverflow.com/questions/5666784/how-can-i-slow-down-a-mysql-dump-as-to-not-affect-current-load-on-the-server backup - How can I slow down a MySQL dump as to not affect current load on the server? - Stack Overflow]</ref>: 
# (optional) install {{kbd | key =pv}} if the {{kbd | key =pv}} was not installed
# (for InnoDB tables){{kbd | key =  <nowiki>mysqldump -h localhost -u username -p --force --single-transaction --default-character-set=utf8 DATA_BASE_NAME | pv | gzip -c > database.sql.gz</nowiki>}} <ref>[http://journal.andrewloe.com/2009/05/12/pv-gzip-mysql/ pv + gzip + mysql — W. Andrew Loe III: Journal]</ref><ref>(if have permission to LOCK TABLES){{kbd | key =  <nowiki>mysqldump -h localhost -u username -p DATA_BASE_NAME | pv | gzip -c > database.sql.gz</nowiki>}} (if have no permission to LOCK TABLES){{kbd | key =  <nowiki>mysqldump -h localhost -u username -p --lock-tables=false DATA_BASE_NAME | pv | gzip -c > database.sql.gz</nowiki>}} via [http://stackoverflow.com/questions/104612/run-mysqldump-without-locking-tables mysql - Run MySQLDump without Locking Tables - Stack Overflow]</ref> and press {{kbd | key =  <nowiki>Enter</nowiki> }}
# ask to enter {{kbd | key =  <nowiki>password</nowiki> }} and press {{kbd | key =  <nowiki>Enter</nowiki> }}

optional: Append the Today's date to file name
* On {{Linux}}: (for InnoDB tables){{kbd | key =  <nowiki>mysqldump -h localhost -u username -p --force --single-transaction --default-character-set=utf8 DATA_BASE_NAME | pv | gzip -c > database.sql.$(date +"%y%m%d").gz</nowiki>}} 

'''method2''': Bulk export individual tables into the multiple compressed *.sql files
<pre>
mysqldump -h localhost -u username -pPASSWORD --force --single-transaction --default-character-set=utf8 DB_NAME TABLE_1 | pv | gzip -c > table_1.sql.gz
mysqldump -h localhost -u username -pPASSWORD --force --single-transaction --default-character-set=utf8 DB_NAME TABLE_2 | pv | gzip -c > table_2.sql.gz
   
</pre>
note: the last line of above part is '''return symbol'''. The last command will not be executed automatically without the return symbol.

'''method3''': export the *.sql file. It will show a progress bar and estimated time to complete the mysqldump <ref>[http://dubbs.github.io/blog/2013/09/05/mysql-import-slash-export-progress-bar/ MySQL Import/Export Progress Bar - Kevin Warrington]</ref>: 
# (optional if the {{kbd | key =pv}} was not installed) {{kbd | key =yum install pv}} for RHEL / CentOS / SL / Fedora Linux
# (for InnoDB tables){{kbd | key =  <nowiki>mysqldump -h localhost -u username -p --force --single-transaction --default-character-set=utf8 DATA_BASE_NAME | pv > database.sql</nowiki>}}  and press {{kbd | key =  <nowiki>Enter</nowiki> }}
# enter {{kbd | key =  <nowiki>password</nowiki> }} and press {{kbd | key =  <nowiki>Enter</nowiki> }}

'''method4''': export the *.sql file
# {{kbd | key =  <nowiki>mysqldump -h localhost -u username -p --single-transaction  --default-character-set=utf8 DATA-BASE-NAME > /path/to/database.sql </nowiki>}}

'''method5''':  Using phpmyadmin to export the database. {{exclaim}} But I found the number rows of table after imported was not the same with the number rows of original table once.

==== Exporting selected data ====
[http://stackoverflow.com/questions/17397661/append-mysql-dump-to-a-table mysqldump - Append MYSQL dump to a table - Stack Overflow] {{access | date = 2016-06-29}}


==== Potential failure issue ====
* insufficient hard-disk space

=== Importing data from MySql sql file ===
{{exclaim}} Notice: existing database will be overwritten

'''method 1''': {{Gd}} Import the compressed *.sql file with gzip (especially for BIG sql file). It will show a progress bar and estimated time to complete the mysql command: 
# (optional) install {{kbd | key =pv}} if the {{kbd | key =pv}} was not installed for RHEL / CentOS / SL / Fedora Linux
# Check if the file is gzip format (test the compressed file integrity) ex: (1) {{kbd | key =  <nowiki>gunzip -t database.sql.gz</nowiki>}} If not, it will return the message "gzip: database.sql.gz: not in gzip format." (2) Using [http://www.winmd5.com/ WinMD5 Free] for {{Win}} or [http://linux.die.net/man/1/md5sum md5sum] command for {{Linux}} to obtain MD5 checksum of files.
# {{kbd | key =  <nowiki> pv database.sql.gz | gunzip | mysql -u username -p -h localhost --default_character_set utf8 --force DATA_BASE_NAME</nowiki>}} <ref>[http://journal.andrewloe.com/2009/05/12/pv-gzip-mysql/ pv + gzip + mysql — W. Andrew Loe III: Journal]</ref> and press {{kbd | key =  <nowiki>Enter</nowiki> }}
# enter {{kbd | key =  <nowiki>password</nowiki> }} and press {{kbd | key =  <nowiki>Enter</nowiki> }} The console window will show ETA (Estimated Time of Arrival)

'''method 2''': Import *.sql file: 
# (optional if the .sql file was compressed) {{kbd | key =unzip data.zip}} or {{kbd | key =gzip -d data.gz}} if the file was compressed by gzip
# {{kbd | key =  <nowiki>mysql -u username -p -h localhost --default_character_set utf8 --force DATA_BASE_NAME < data.sql</nowiki>}} <ref>[http://www.cyberciti.biz/faq/import-mysql-dumpfile-sql-datafile-into-my-database/ Import MySQL Dumpfile, SQL Datafile Into My Database]</ref> and press {{kbd | key =  <nowiki>Enter</nowiki> }}
# enter {{kbd | key =  <nowiki>password</nowiki> }} and press {{kbd | key =  <nowiki>Enter</nowiki> }}

'''method 3''': Import the *.sql file (especially for BIG sql file). It will show a progress bar and estimated time to complete the mysql command<ref>[http://dba.stackexchange.com/questions/17367/how-can-i-monitor-the-progress-of-an-import-of-a-large-sql-file mysql - How can I monitor the progress of an import of a large .sql file? - Database Administrators Stack Exchange]</ref>: 
# (optional if the {{kbd | key =pv}} was not installed) {{kbd | key =yum install pv}} for RHEL / CentOS / SL / Fedora Linux
# {{kbd | key =  <nowiki>pv data.sql | mysql -u username -p -h localhost --default_character_set utf8 --force DATA_BASE_NAME</nowiki>}} <ref>[http://www.cyberciti.biz/faq/import-mysql-dumpfile-sql-datafile-into-my-database/ Import MySQL Dumpfile, SQL Datafile Into My Database]</ref> and press {{kbd | key =  <nowiki>Enter</nowiki> }}
# enter {{kbd | key =  <nowiki>password</nowiki> }} and press {{kbd | key =  <nowiki>Enter</nowiki> }} The console window will show ETA (Estimated Time of Arrival)

'''method 4''': Import ZIP file to MySql directly:
# (optional if the 7Zip was not installed) {{kbd | key =yum install p7zip}}
# {{kbd | key = <nowiki>7za x -so data.zip | mysql -u username -p -h localhost --default_character_set utf8 --force DATA_BASE_NAME</nowiki>}} <ref>[http://stackoverflow.com/questions/11267309/importing-zipped-files-in-mysql-using-command-line database - Importing zipped files in Mysql using command line - Stack Overflow]</ref><ref>[http://needs-be.blogspot.tw/2011/01/install-7zip-on-centos-55.html Install 7Zip on CentOS 5.5]</ref> and press {{kbd | key =  <nowiki>Enter</nowiki> }}
# enter {{kbd | key =  <nowiki>password</nowiki> }} and press {{kbd | key =  <nowiki>Enter</nowiki> }}

=== Synchronizing databases ===
Synchronizing two MySQL databases:
* [http://www.heidisql.com/ HeidiSQL - MySQL, MSSQL and PostgreSQL made easy] v.9.4.0.5125 for {{Win}}, {{Mac}} & {{Linux}}
** Steps: Choose the database or table --> Export database as SQL --> Output: Select the mysql server connection
** Scheduler: Not available<ref>[http://www.heidisql.com/forum.php?t=22040 Schedule backups/exports]</ref> {{exclaim}}. Manually synchronizing databases between two different servers.
* [https://dev.mysql.com/doc/refman/5.7/en/replication.html Replication]
** Steps:
** Scheduler: Auto {{Gd}}.
* ''$'' [https://www.webyog.com/product/sqlyog SQLyog] v.12.4.0 for {{Win}}.
** Steps: Menu --> Powertools --> Database Synchronization Wizard
** Scheduler: Available {{Gd}}. Save the job file & Schedule it using Windows scheduler.

Transfer date from MS SQL server to MySQL server: 
* ''$'' [https://www.webyog.com/product/sqlyog SQLyog] for {{Win}}. Use a query to specify the data to transfer from MS SQL server into MySQL server.

=== Show the MySQL process list & kill the process ===
Show the MySQL process list & kill the process (especial for SLOW query command)<ref>[http://dev.mysql.com/doc/refman/5.1/en/show-processlist.html MySQL :: MySQL 5.1 Reference Manual :: 13.7.5.31 SHOW PROCESSLIST Syntax]</ref>
# {{kbd | key=mysql -h HOST -u ACCOUNT -p }}
# And keyin the PASSWORD of your MySQL ACCOUNT. The first character will be changed to ''mysql>'' from ''$'' or ''#''
# mysql> 
#* {{kbd | key=SHOW FULL PROCESSLIST\G}} to show the process list
#* {{kbd | key=SHOW PROCESSLIST\G}} to show the brief process list
# mysql> {{kbd | key=kill 101;}} to kill the process with Id number: 101
# mysql> {{kbd | key=exit;}} to leave the MySQL command.

=== Troubleshooting of MySQL ===
==== command not found: mysqldump ====
# locate the mysqldump command
#* {{kbd | key=<nowiki>sudo find / -iname mysqldump</nowiki>}} for {{Mac}} or {{Linux}}
#* And find {{kbd | key=<nowiki>/Applications/XAMPP/xamppfiles/bin/mysqldump</nowiki>}} from [https://www.apachefriends.org/index.html XAMPP] for {{Mac}}
# input the complete path of mysqldump command
#* old command which caused error {{kbd | key=<nowiki>mysqldump -h 127.0.0.1 -u root -p  --force --single-transaction DATABASE_NAME | pv | gzip -c > DATABASE_NAME.sql.gz</nowiki>}}
#* new command {{kbd | key=<nowiki>/Applications/XAMPP/xamppfiles/bin/mysqldump -h 127.0.0.1 -u root -p  --force --single-transaction DATABASE_NAME | pv | gzip -c > DATABASE_NAME.sql.gz</nowiki>}}

==== could not access the mysql log ====
Version: XAMPP 5.6.15-1 on {{Mac}}

Cause:
* the error log only be accessed by the mysql user

Solution <ref>[http://computerplumber.com/2009/01/using-the-chmod-command-effectively/ Using the CHMOD command effectively @ Computer Plumber]</ref>:
<pre>
find the path to the mysql log
$ ls /Applications/XAMPP/xamppfiles/var/mysql/*.local.err

find the file name of mysql log ex: XXXMacBook-Pro.local.err

set the permission of log
$ sudo chmod 774 /Applications/XAMPP/xamppfiles/var/mysql/XXXMacBook-Pro.local.err
</pre>

==== could not open single-table tablespace file filename.ibd ====
Version: XAMPP 5.6.15-1 on {{Mac}}

Condition: The Mac was shutdown accidentally and the database was not shutdown normally. After reboot the Mac, unable to start the MySQL service<ref>[http://stackoverflow.com/questions/35184367/error-could-not-open-single-table-tablespace-file-scrapers-records-ibd mysql - Error: could not open single-table tablespace file .\scrapers\records.ibd - Stack Overflow]</ref><ref>[http://chepri.com/our-blog/mysql-innodb-corruption-and-recovery/ MySQL Won't Start - InnoDB Corruption and Recovery. - Chepri]</ref>.

Possible solution: 
# Edit the MySQL configuration file located: /Applications/XAMPP/xamppfiles/etc/my.cnf
# Add this line: {{kbd | key=<nowiki>innodb_force_recovery = 1</nowiki>}}
# Try to start the MySQL service
# If the MySQL service started successfully, edit the MySQL configuration file and mark this line : {{kbd | key=<nowiki>#innodb_force_recovery = 1</nowiki>}}
# Restart the MySQL service

==== ERROR 1005 (HY000) at line xx: Can't create table 'TABLE_NAME' (errno: 28) ====

Solutions
* Check if the disk space where mysql data folder located is enough. e.g. Input {{kbd | key=df -h}} on {{Linux}}
* More on [http://stackoverflow.com/questions/11045279/error-1005-hy000-cant-create-table-errno-150 mysql - ERROR 1005 (HY000): Can't create table (errno: 150) - Stack Overflow].

==== ERROR 1006 (HY000): Can't create database 'DATABASE_NAME' (errno: 28) ====
Solutions
* Check if the disk space where mysql data folder located is enough. e.g. Input {{kbd | key=df -h}} on {{Linux}}
* More on [http://stackoverflow.com/questions/18719748/error-1006-hy000-cant-create-database-errno-13-mysql-5-6-12 ERROR 1006 (HY000) Can't create database (errno: 13) MySQL 5.6.12 - Stack Overflow].

==== ERROR 1045 (28000): Access denied for user 'user'@'localhost' (using password: YES) ====
Solution:
* Check the typo of user name.
* Check the typo of password.
* If you are using the console command, escape the password if it contains special characters e.g. {{kbd | key=<nowiki>mysql -u root -p'PASSWORD'</nowiki>}}<ref>[http://superuser.com/questions/123928/escaping-a-password-using-mysqldump-console escape characters - Escaping a password using mysqldump console - Super User]</ref>
* You may need to delete the existing account setting and re-config again.

==== Err 1054 - Unknown column in 'where clause' ====
Message: [Err] 1054 - Unknown column 'xxx' in 'where clause'

Solution:
# check the column name 'xxx' if exists
# if the column name 'xxx' was computed by the [http://dev.mysql.com/doc/refman/5.7/en/example-user-variables.html User-Defined Variables]. Enclosed the whole query into another parent derived query.
<pre>
-- The query which met the error message: [Err] 1054 - Unknown column 'rank' in 'where clause'
SELECT semi.*, IF(semi.id = semi.prev, @rank := @rank +1, @rank := 1 ) AS `rank`   
FROM
(
        ...
) semi
WHERE semi.rank <= 10
</pre>

Enclosed the whole query into another parent derived query.
<pre>
SELECT final.*
FROM
(
        SELECT semi.*, IF(semi.id = semi.prev, @rank := @rank +1, @rank := 1 ) AS `rank`   
        FROM
        (
                ...
        ) semi
) final
WHERE final.rank <= 10
</pre>

==== ERROR 1827 (HY000): The password hash doesn't have the expected format. Check if the correct password algorithm is being used with the PASSWORD() function. ====
Wrong sql query as follows:
<pre>
CREATE USER 'test'@'localhost' IDENTIFIED BY PASSWORD 'my_password';
</pre>

Solution:
(1) Check if the account was created or not
<pre>
SELECT User,Host FROM mysql.user;
</pre>

(2a) If the account was created, set the password for the account.
<pre>
SET PASSWORD FOR 'test'@'localhost' = PASSWORD('my_password');
</pre>

(2b) If the account was NOT created, re-create the account.
<pre>
CREATE USER 'test'@'localhost' IDENTIFIED BY 'my_password';
</pre>

references
* [http://dev.mysql.com/doc/refman/5.7/en/create-user.html MySQL :: MySQL 5.7 Reference Manual :: 14.7.1.2 CREATE USER Syntax]
* [http://dev.mysql.com/doc/refman/5.7/en/set-password.html MySQL :: MySQL 5.7 Reference Manual :: 14.7.1.7 SET PASSWORD Syntax]
* [http://dev.mysql.com/doc/refman/5.7/en/drop-user.html MySQL :: MySQL 5.7 Reference Manual :: 14.7.1.3 DROP USER Syntax]

==== ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysql.sock' ====
Condition on Cygwin terminal of Windows:
<pre>
$ mysql -u root -p
Enter password:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysql.sock' (2)

$ mysql -h localhost -u root -p
Enter password:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysql.sock' (2)
</pre>

Solution:
* Change {{kbd | key=<nowiki>-h localhost</nowiki>}} to {{kbd | key=<nowiki>-h 127.0.0.1</nowiki>}}
<pre>
$ mysql -h 127.0.0.1 -u root -p
</pre>

==== ERROR 2003 (HY000): Can't connect to MySQL server on '127.0.0.1' (111 "Connection refused") ====

Solution:
* Check if the MySQL service is running or not<ref>[https://www.cyberciti.biz/faq/how-to-find-out-if-mysql-is-running-on-linux/ HowTo: Find out If MySQL Is Running On Linux Or Not]</ref>. If not, start the MySQL service.

==== ERROR 2003 (HY000): Can't connect to MySQL server on 'IP' (116 "Connection timed out") ====
Solution:
* Check the permission of MySQL database user.
* Check the firewall rules. More on [https://devops.profitbricks.com/tutorials/install-mysql-on-centos-7/#firewall-rules Install MySQL on CentOS 7 | ProfitBricks DevOps Central] 
** Check if your IP address was included in the allowed IP address list of firewall rules.
** Check if your IP address was changed by using [https://whatismyipaddress.com/ What Is My IP Address?] services.
References:
* [https://support.rackspace.com/how-to/mysql-connect-to-your-database-remotely/ Connect to a MySQL database remotely]

==== Error Code: 2013. Lost connection to MySQL server during query ====
Condition: After executed the following query contains number of rows which exceed 1,000,000 rows, I met the error message 'Error Code: 2013. Lost connection to MySQL server during query'.
<pre>
INSERT IGNORE INTO `target`.`table` SELECT * FROM `source`.`table`;
</pre>

Solution:
* Increase the setting of '''DBMS connection read time out (in seconds)''' on [https://www.mysql.com/products/workbench/ MySQL Workbench]. <ref>[http://stackoverflow.com/questions/16877574/how-can-i-execute-sql-queries-that-take-longer-99-999-seconds-on-mysql-workbench How can I execute SQL queries that take longer 99,999 seconds on MySQL Workbench? - Stack Overflow]</ref><ref>[http://stackoverflow.com/questions/10563619/error-code-2013-lost-connection-to-mysql-server-during-query Error Code: 2013. Lost connection to MySQL server during query - Stack Overflow]</ref>
* Reduce the number of rows to reduce the execution time (1) by using {{kbd | key=LIMIT}} clause (2) or by splitting the query size e.g. {{kbd | key=<nowiki>MOD(column, 2) = 0</nowiki>}} & {{kbd | key=<nowiki>MOD(column, 2) > 0</nowiki>}} if the column is numeric.
<pre>
INSERT IGNORE INTO `target`.`table` SELECT * FROM `source`.`table` LIMIT 0, 10000;
</pre>

==== Navicat error:  [Exp] OLE error 800A03EC ====
error message:
<pre>
[Msg] [Exp] Export to - test.xlsx
[Err] [Row1048576] [Exp] OLE error 800A03EC
[Err] [Row1048577] [Exp] OLE error 800A03EC
[Err] [Row1048578] [Exp] OLE error 800A03EC
[Err] [Row1048579] [Exp] OLE error 800A03EC
</pre>

cause:
* exceeds the [[Microsoft Excel]] Worksheet size: 1,048,576 rows

solution:
* LIMIT the rows of MySQL query

==== resolve insufficient hard disk space where mysql data located ====
[http://errerrors.blogspot.tw/2016/07/mysql.html Err: 解決 MySQL 資料庫所在硬碟空間不足的狀況]

=== further reading ===
* [http://dev.mysql.com/doc/refman/5.7/en/error-handling.html MySQL :: MySQL 5.7 Reference Manual :: B Errors, Error Codes, and Common Problems]
* [http://eosrei.net/articles/2013/03/forcing-mysqldump-always-be-nice-cpu-and-io Forcing a mysqldump to always be nice to CPU and I/O | eosrei.net]: using [http://www.computerhope.com/unix/unice.htm nice] or [http://www.tutorialspoint.com/unix_commands/ionice.htm ionice] commands {{exclaim}} 
** ionice command is not exists in cygwin
* [http://www.dbastuff.net/2014/09/mysql-dump-and-partitions.html DBAStuff: Mysql Dump and partitions] {{access | date = 2016-01-01}}
* [https://dev.mysql.com/doc/refman/5.5/en/backup-methods.html MySQL :: MySQL 5.5 Reference Manual :: 7.2 Database Backup Methods]  {{access | date = 2016-06-29}}
* [[SQL syntax debug]]

=== references ===
<references/>



[[Category:MySQL]]
[[Category:Data Science]]