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MariaDB
===============
Starting / Stopping / Restarting
-----------
Start MariaDB: `service mysql start`
Stop MariaDB: `service mysql stop`
Restart MariaDB: `service mysql restart`
Status MariaDB: `service mysql status`
Commands
-----------
Access monitor: `mysql -u [username] -p` (will prompt for password)
Show all databases: `show databases;`
Access database: `mysql -u [username] -p [database]` (will prompt for password)
Create new database: `create database [database];`
Select database: `use [database];`
Determine what database is in use: `select database();`
Show all tables: `show tables;`
Show table structure: `describe [table];`
List all indexes on a table: `show index from [table];`
Create new table with columns: `CREATE TABLE [table] ([column] VARCHAR(120), [another-column] DATETIME);`
Adding a column: `ALTER TABLE [table] ADD COLUMN [column] VARCHAR(120);`
Adding a column with an unique, auto-incrementing ID: `ALTER TABLE [table] ADD COLUMN [column] int NOT NULL AUTO_INCREMENT PRIMARY KEY;`
Inserting a record: `INSERT INTO [table] ([column], [column]) VALUES ('[value]', [value]');`
MySQL function for datetime input: `NOW()`
Selecting records: `SELECT * FROM [table];`
Explain records: `EXPLAIN SELECT * FROM [table];`
Selecting parts of records: `SELECT [column], [another-column] FROM [table];`
Counting records: `SELECT COUNT([column]) FROM [table];`
Counting and selecting grouped records: `SELECT *, (SELECT COUNT([column]) FROM [table]) AS count FROM [table] GROUP BY [column];`
Selecting specific records: `SELECT * FROM [table] WHERE [column] = [value];` (Selectors: `<`, `>`, `!=`; combine multiple selectors with `AND`, `OR`)
Select records containing `[value]`: `SELECT * FROM [table] WHERE [column] LIKE '%[value]%';`
Select records starting with `[value]`: `SELECT * FROM [table] WHERE [column] LIKE '[value]%';`
Select records starting with `val` and ending with `ue`: `SELECT * FROM [table] WHERE [column] LIKE '[val_ue]';`
Select a range: `SELECT * FROM [table] WHERE [column] BETWEEN [value1] and [value2];`
Select with custom order and only limit: `SELECT * FROM [table] WHERE [column] ORDER BY [column] ASC LIMIT [value];` (Order: `DESC`, `ASC`)
Updating records: `UPDATE [table] SET [column] = '[updated-value]' WHERE [column] = [value];`
Deleting records: `DELETE FROM [table] WHERE [column] = [value];`
Delete *all records* from a table (without dropping the table itself): `DELETE FROM [table];`
(This also resets the incrementing counter for auto generated columns like an id column.)
Delete all records in a table: `truncate table [table];`
Removing table columns: `ALTER TABLE [table] DROP COLUMN [column];`
Deleting tables: `DROP TABLE [table];`
Deleting databases: `DROP DATABASE [database];`
Custom column output names: `SELECT [column] AS [custom-column] FROM [table];`
Export a database dump (more info [here](http://stackoverflow.com/a/21091197/1815847)): `mysqldump -u [username] -p [database] > db_backup.sql`
Use `--lock-tables=false` option for locked tables (more info [here](http://stackoverflow.com/a/104628/1815847)).
Import a database dump (more info [here](http://stackoverflow.com/a/21091197/1815847)): `mysql -u [username] -p -h localhost [database] < db_backup.sql`
Logout: `exit;`
Aggregate functions
-----------
Select but without duplicates: `SELECT distinct name, email, acception FROM owners WHERE acception = 1 AND date >= 2015-01-01 00:00:00`
Calculate total number of records: `SELECT SUM([column]) FROM [table];`
Count total number of `[column]` and group by `[category-column]`: `SELECT [category-column], SUM([column]) FROM [table] GROUP BY [category-column];`
Get largest value in `[column]`: `SELECT MAX([column]) FROM [table];`
Get smallest value: `SELECT MIN([column]) FROM [table];`
Get average value: `SELECT AVG([column]) FROM [table];`
Get rounded average value and group by `[category-column]`: `SELECT [category-column], ROUND(AVG([column]), 2) FROM [table] GROUP BY [category-column];`
Multiple tables
-----------
Select from multiple tables: `SELECT [table1].[column], [table1].[another-column], [table2].[column] FROM [table1], [table2];`
Combine rows from different tables: `SELECT * FROM [table1] INNER JOIN [table2] ON [table1].[column] = [table2].[column];`
Combine rows from different tables but do not require the join condition: `SELECT * FROM [table1] LEFT OUTER JOIN [table2] ON [table1].[column] = [table2].[column];` (The left table is the first table that appears in the statement.)
Rename column or table using an _alias_: `SELECT [table1].[column] AS '[value]', [table2].[column] AS '[value]' FROM [table1], [table2];`
Users functions
-----------
List all users: `SELECT User,Host FROM mysql.user;`
Create new user: `CREATE USER 'username'@'localhost' IDENTIFIED BY 'password';`
Create new remote user: `CREATE USER 'username'@'%' IDENTIFIED BY 'password';`
Grant `ALL` access to user for `*` tables: `GRANT ALL ON database.* TO 'user'@'localhost';`
Grant `ALL` access to remote user for `*` tables: `GRANT ALL ON database.* TO 'user'@'%';`
Find out the IP Address of the Mysql Host
-----------
`SHOW VARIABLES WHERE Variable_name = 'hostname';` ([source](http://serverfault.com/a/129646))