sql

mysql/README.md

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