164 lines
5.9 KiB
Markdown
164 lines
5.9 KiB
Markdown
---
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title: MySql
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category: Databases
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---
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### Create / Delete Database
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CREATE DATABASE dbNameYouWant
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CREATE DATABASE dbNameYouWant CHARACTER SET utf8
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DROP DATABASE dbNameYouWant
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ALTER DATABASE dbNameYouWant CHARACTER SET utf8
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### Backup Database to SQL File
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mysqldump -u Username -p dbNameYouWant > databasename_backup.sql
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### Restore from backup SQL File
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mysql - u Username -p dbNameYouWant < databasename_backup.sql
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### Repair Tables After Unclean Shutdown
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mysqlcheck --all-databases
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mysqlcheck --all-databases --fast
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### Browsing
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SHOW DATABASES
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SHOW TABLES
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SHOW FIELDS FROM table / DESCRIBE table
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SHOW CREATE TABLE table
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SHOW PROCESSLIST
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KILL process_number
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### Select
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SELECT * FROM table
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SELECT * FROM table1, table2, ...
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SELECT field1, field2, ... FROM table1, table2, ...
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SELECT ... FROM ... WHERE condition
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SELECT ... FROM ... WHERE condition GROUPBY field
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SELECT ... FROM ... WHERE condition GROUPBY field HAVING condition2
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SELECT ... FROM ... WHERE condition ORDER BY field1, field2
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SELECT ... FROM ... WHERE condition ORDER BY field1, field2 DESC
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SELECT ... FROM ... WHERE condition LIMIT 10
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SELECT DISTINCT field1 FROM ...
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SELECT DISTINCT field1, field2 FROM ...
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### Select - Join
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SELECT ... FROM t1 JOIN t2 ON t1.id1 = t2.id2 WHERE condition
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SELECT ... FROM t1 LEFT JOIN t2 ON t1.id1 = t2.id2 WHERE condition
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SELECT ... FROM t1 JOIN (t2 JOIN t3 ON ...) ON ...
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### Conditions
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field1 = value1
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field1 <> value1
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field1 LIKE 'value _ %'
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field1 IS NULL
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field1 IS NOT NULL
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field1 IS IN (value1, value2)
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field1 IS NOT IN (value1, value2)
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condition1 AND condition2
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condition1 OR condition2
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### Insert
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INSERT INTO table1 (field1, field2, ...) VALUES (value1, value2, ...)
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### Delete
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DELETE FROM table1 / TRUNCATE table1
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DELETE FROM table1 WHERE condition
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DELETE FROM table1, table2 FROM table1, table2 WHERE table1.id1 =
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table2.id2 AND condition
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### Update
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UPDATE table1 SET field1=new_value1 WHERE condition
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UPDATE table1, table2 SET field1=new_value1, field2=new_value2, ... WHERE
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table1.id1 = table2.id2 AND condition
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### Create / Delete / Modify Table
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*Create*
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CREATE TABLE table (field1 type1, field2 type2, ...)
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CREATE TABLE table (field1 type1, field2 type2, ..., INDEX (field))
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CREATE TABLE table (field1 type1, field2 type2, ..., PRIMARY KEY (field1))
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CREATE TABLE table (field1 type1, field2 type2, ..., PRIMARY KEY (field1,
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field2))
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CREATE TABLE table1 (fk_field1 type1, field2 type2, ...,
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FOREIGN KEY (fk_field1) REFERENCES table2 (t2_fieldA))
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[ON UPDATE|ON DELETE] [CASCADE|SET NULL]
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CREATE TABLE table1 (fk_field1 type1, fk_field2 type2, ...,
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FOREIGN KEY (fk_field1, fk_field2) REFERENCES table2 (t2_fieldA, t2_fieldB))
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CREATE TABLE table IF NOT EXISTS (...)
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CREATE TEMPORARY TABLE table (...)
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*Drop*
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DROP TABLE table
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DROP TABLE IF EXISTS table
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DROP TABLE table1, table2, ...
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*Alter*
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ALTER TABLE table MODIFY field1 type1
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ALTER TABLE table MODIFY field1 type1 NOT NULL ...
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ALTER TABLE table CHANGE old_name_field1 new_name_field1 type1
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ALTER TABLE table CHANGE old_name_field1 new_name_field1 type1 NOT NULL ...
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ALTER TABLE table ALTER field1 SET DEFAULT ...
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ALTER TABLE table ALTER field1 DROP DEFAULT
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ALTER TABLE table ADD new_name_field1 type1
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ALTER TABLE table ADD new_name_field1 type1 FIRST
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ALTER TABLE table ADD new_name_field1 type1 AFTER another_field
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ALTER TABLE table DROP field1
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ALTER TABLE table ADD INDEX (field);
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*Change field order*
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ALTER TABLE table MODIFY field1 type1 FIRST
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ALTER TABLE table MODIFY field1 type1 AFTER another_field
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ALTER TABLE table CHANGE old_name_field1 new_name_field1 type1 FIRST
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ALTER TABLE table CHANGE old_name_field1 new_name_field1 type1 AFTER
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another_field
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### Keys
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CREATE TABLE table (..., PRIMARY KEY (field1, field2))
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CREATE TABLE table (..., FOREIGN KEY (field1, field2) REFERENCES table2
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(t2_field1, t2_field2))
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### Users and Privileges
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GRANT ALL PRIVILEGES ON base.* TO 'user'@'localhost' IDENTIFIED BY 'password';
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GRANT SELECT, INSERT, DELETE ON base.* TO 'user'@'localhost' IDENTIFIED BY 'password';
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REVOKE ALL PRIVILEGES ON base.* FROM 'user'@'host'; -- one permission only
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REVOKE ALL PRIVILEGES, GRANT OPTION FROM 'user'@'host'; -- all permissions
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SET PASSWORD = PASSWORD('new_pass')
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SET PASSWORD FOR 'user'@'host' = PASSWORD('new_pass')
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SET PASSWORD = OLD_PASSWORD('new_pass')
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DROP USER 'user'@'host'
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host ‘%’ indicates any host.
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### Main Data Types
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TINYINT (1o: -217+128) SMALLINT (2o: +-65 000)
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MEDIUMINT (3o: +-16 000 000) INT (4o: +- 2 000 000 000)
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BIGINT (8o: +-9.10^18)
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Precise interval: -(2^(8*N-1)) -> (2^8*N)-1
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/!\ INT(2) = "2 digits displayed" -- NOT "number with 2 digits max"
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FLOAT(M,D) DOUBLE(M,D) FLOAT(D=0->53)
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/!\ 8,3 -> 12345,678 -- NOT 12345678,123!
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TIME (HH:MM) YEAR (AAAA) DATE (AAAA-MM-JJ) DATETIME (AAAA-MM-JJ HH:MM; années 1000->9999)
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TIMESTAMP (like DATETIME, but 1970->2038, compatible with Unix)
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VARCHAR (single-line; explicit size) TEXT (multi-lines; max size=65535) BLOB (binary; max size=65535)
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Variants for TEXT&BLOB: TINY (max=255) MEDIUM (max=~16000) LONG (max=4Go)
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Ex: VARCHAR(32), TINYTEXT, LONGBLOB, MEDIUMTEXT
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ENUM ('value1', 'value2', ...) -- (default NULL, or '' if NOT NULL)
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### Reset Root Password
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$ /etc/init.d/mysql stop
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$ mysqld_safe --skip-grant-tables
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$ mysql # on another terminal
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mysql> UPDATE mysql.user SET password=PASSWORD('new_pass') WHERE user='root';
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## Switch back to the mysqld_safe terminal and kill the process using Control + \
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$ /etc/init.d/mysql start</code>
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