340 lines
7.2 KiB
Markdown
340 lines
7.2 KiB
Markdown
---
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gitea: none
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include_toc: true
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---
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# MySQL
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Für **Joins**, siehe auch: [Roger SQL Join Tutorial](files/Roger_SQL_Join_Tut.docx)
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---
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## System
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### Which MySQL is running?
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Für 5.7.x versionen... Percona, Oracle...
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``` sql
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SELECT SUBSTR(variable_value,1,
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LOCATE(' ',variable_value) - 1) DBVersion
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FROM information_schema.global_variables
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WHERE variable_name='version_comment';
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```
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### Show global variables
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``` sql
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SHOW GLOBAL VARIABLES;
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SHOW GLOBAL VARIABLES LIKE 'innodb%';
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SHOW GLOBAL VARIABLES LIKE 'innodb_rollback_on_timeout';
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```
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### Set global variables
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Only until next MySQL restart. For permanent change, use my.cnf under the [mysqld] header.
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``` sql
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SET GLOBAL innodb_lock_wait_timeout = 320;
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```
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---
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## Users, Grants
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### set root password
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``` sql
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ALTER USER 'root'@'localhost' IDENTIFIED WITH caching_sha2_password BY 'password';
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FLUSH PRIVILEGES;
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```
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siehe auch https://linuxhint.com/change-mysql-root-password-ubuntu/
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### Show users
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``` sql
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SELECT host,user,authentication_string FROM mysql.user;
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```
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### Add user
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``` sql
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CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'password';
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```
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version 8.0
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``` sq
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nCREATE USER 'newuser'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';
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```
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### Show grants for user
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``` sql
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SHOW GRANTS FOR 'user_name'@'host';
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```
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### Grant
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also see: https://www.digitalocean.com/community/tutorials/how-to-create-a-new-user-and-grant-permissions-in-mysql#how-to-grant-different-user-permissions
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``` sql
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GRANT ALL PRIVILEGES ON *.* TO 'newuser'@'localhost'; # give full root privileges
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GRANT ALL PRIVILEGES ON db1.* TO 'newuser'@'localhost'; # give privileges for database db1
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FLUSH PRIVILEGES;
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```
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### Revoke
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``` sql
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REVOKE type_of_permission ON database_name.* FROM 'username'@'localhost';
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FLUSH PRIVILEGES;
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```
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### Change Password for user
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``` sql
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ALTER USER 'user-name'@'localhost' IDENTIFIED BY 'NEW_USER_PASSWORD';
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FLUSH PRIVILEGES;
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# or
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UPDATE mysql.user SET authentication_string = PASSWORD('MyNewPass')
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WHERE User = 'username' AND Host = 'localhost';
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FLUSH PRIVILEGES;
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```
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---
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## Database
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### Drop DB
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``` sql
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DROP DATABASE IF EXISTS database_name;
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```
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### Export DB
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```
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mysqldump -h mariadb-p01.infra.vs.ch -P 33003 -uingest -p --routines --lock-tables=false --single-transaction atom > ~/atomp-01-20210425.sql
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```
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Windows
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```
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mysqldump -h mariadb-p01.infra.vs.ch -P 33003 -uingest -p --routines --lock-tables=false --single-transaction atom --result-file="c:\atomp-01-20210425.sql"
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```
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Falls Fehler `mysqldump: Couldn't execute 'SELECT COLUMN_NAME, JSON_EXTRACT.....` diese Option noch mit einbeziehen
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`--column-statistics=0`
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See also https://www.linode.com/docs/guides/use-mysqldump-to-back-up-mysql-or-mariadb/
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### Import DB
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```
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mysql -uusername -p db_name < /path/to/file.sql
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```
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Falls komprimierter dump:
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```
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gunzip < file.sql.gz | mysql -uusername -p db_name
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```
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### Create DB
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```
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mysql -h localhost -u root -p -e "CREATE DATABASE atom CHARACTER SET utf8 COLLATE utf8_unicode_ci;"
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```
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### Get Database Properties
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``` sql
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SELECT default_character_set_name, default_collation_name FROM information_schema.schemata WHERE schema_name = 'dar416';
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```
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---
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## Tables
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### Count rows in all tables
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``` sql
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select sum(TABLE_ROWS) from information_schema.tables where table_schema = 'db-name';
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```
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### Count rows in each table
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``` sql
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SELECT table_name, table_rows FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'db-name';
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```
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### Export/dump single table
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```
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mysqldump db_name table_name > table_name.sql
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```
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### Import single table
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```
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mysql -u username -p db_name < /path/to/table_name.sql
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```
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### Drop Tables
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``` sql
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DROP TABLE IF EXIST [table 1], [table 2], [table n];
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```
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### Select over single table
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#### SELECT mit GROUP BY und HAVING
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``` sql
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SELECT post_title, COUNT(*) c
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FROM wp_posts
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WHERE post_type='article'
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AND post_author=1
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GROUP BY post_title
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HAVING c > 1
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```
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#### Select to file
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```
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mysql -uroot -e "use atom_A; select io.identifier, io.id, information_object_i18n.title from information_object io left join information_object_i18n on io.id = information_object_i18n.id where io.identifier IS NULL or io.identifier like '#%' or io.identifier = '?' order by identifier;" > /home/ubuntu/identifier_not_number.csv
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```
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#### List rows that have the same value in a column
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``` sql
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SELECT ve.vrzng_enht_id, vebhltn.bhltn_id
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FROM vws_vrzng_enht_grund_daten ve,
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vws_vrzng_enht_bhltn vebhltn
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WHERE vebhltn.vrzng_enht_id = ve.vrzng_enht_id
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AND vebhltn.bhltn_id IN(
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SELECT vebhltn.bhltn_id FROM vws_vrzng_enht_bhltn vebhltn
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GROUP BY vebhltn.bhltn_id HAVING COUNT(*) > 1
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)
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```
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### List duplicates (grouped), with additional col "found duplicates"
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``` sql
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SELECT post_title, COUNT(post_title)
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FROM wp_posts
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WHERE post_type = 'article'
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AND post_status = 'publish'
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AND post_title NOT LIKE 'Der Chart des Tages'
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GROUP BY post_title
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HAVING COUNT(post_title) >= 2;
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# or, if all fields should be visible:
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SELECT *, count(post_title)
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FROM wp_posts
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WHERE post_type = 'article'
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AND post_status = 'publish'
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AND post_title NOT LIKE 'Der Chart des Tages'
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GROUP BY post_title
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HAVING count(post_title) >= 2
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```
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### Select over multiple tables
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#### SELECT with LEFT JOIN
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``` sql
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SELECT fuw_master.*, fuw_master_variation.name
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FROM fuw_master
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LEFT JOIN fuw_master_variation
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ON fuw_master.id = fuw_master_variation.id_master;
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```
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### Create
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#### Table with columns from 2 tables (using JOIN)
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``` sql
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CREATE TABLE fuw_master_2
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SELECT fuw_master.*, fuw_master_variation.name
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FROM fuw_master
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LEFT JOIN fuw_master_variation
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ON fuw_master.id = fuw_master_variation.id_master;
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```
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### Insert
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``` sql
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INSERT INTO blabla (spaltenname1, spaltenname2) VALUES ('wert1', 123)
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```
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### Update
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``` sql
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UPDATE table_name SET field1 = new-value1, field2 = new-value2
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[WHERE Clause]
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```
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With replace:
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``` sql
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UPDATE table_name SET field_name = REPLACE(field_name,
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string_to_find,
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string_to_replace)
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[WHERE Clause]
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```
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With joins:
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``` sql
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UPDATE information_object_i18n AS io
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LEFT JOIN property p1
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ON p1.object_id = io.id
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LEFT JOIN property_i18n p2
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ON p1.id = p2.id
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SET io.title = CONCAT('recovery_failed_', io.title)
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WHERE p1.name LIKE 'PID'
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AND p2.value = 'CH-000-0:1234';
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```
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### Export from command line
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```
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mysql>SELECT * FROM tablexy
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INTO OUTFILE 'path/outfile.csv'
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FIELDS TERMINATED BY ','
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ENCLOSED BY '"',
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ESCAPED BY '',
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LINES TERMINATED BY '\n'
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```
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`path` muss meistens dem Pfad entsprechen, der unter `select @@secure_file_priv;` gesetzt ist!
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---
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## Version Upgrade 5.7 to 8.0 ##
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- https://dev.mysql.com/doc/refman/8.0/en/upgrade-binary-package.html
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- https://tastethelinux.com/2020/09/14/upgrade-mysql-server-from-5-7-to-8-ubuntu-18-04/
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## Install 5.7 on Ubuntu 20
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- https://www.vultr.com/docs/how-to-install-mysql-5-7-on-ubuntu-20-04/
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## Fehlermeldungen
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### Error "1038 Out of memory, consider increasing server sort buffer size
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- https://www.skynats.com/blog/error-1038-mysql-memory-allocation-error/
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### Disk voll wegen zu vielen binlogs
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In `/var/lib/mysql` sind zu viele binlogs. Lösung: auf nur 1 Woche reduzieren. Binlogs werden für Restorte gebraucht.
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- mysql service stoppen
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- `/etc/mysql/conf.d/mysql.cnf` erweitern um: `binlog_expire_logs_seconds=604800`
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- mysql neu starten
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