100 lines
4.7 KiB
Markdown
100 lines
4.7 KiB
Markdown
---
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tags:
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- Cheetsheet
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---
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Data Definition Language (DDL)
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------------------------------
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| Command | Description |
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| --- | --- |
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| `CREATE DATABASE <db>` | Create a new database |
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| `DROP DATABASE <db>` | Delete a database |
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| `CREATE TABLE <table> (<column_1> <column_1_type>, <column_2> <column_2_type>)` | Create a new table |
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| `DROP TABLE <table>` | Delete a table |
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| `ALTER TABLE <table> ADD COLUMN <column> <column_type>` | Add a new column to a table |
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| `ALTER TABLE <table> DROP COLUMN <column>` | Remove a column from a table |
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| `ALTER TABLE <table> RENAME COLUMN <column> TO <new_column>` | Rename a column in a table |
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| `ALTER TABLE <table> RENAME TO <new_column>` | Rename a table |
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| `TRUNCATE TABLE <table>` | Remove all rows from a table |
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| `CREATE INDEX INDEXNAME ON <table> (<column>)` | Create an index on a table |
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| `DROP INDEX INDEXNAME` | Remove an index from a table |
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Data Manipulation Language (DML)
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| Command | Description |
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| --- | --- |
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| `INSERT INTO <table> (<column_1>, <column_2>) VALUES (<value_1>, <value_2>)` | Insert a new row into a table |
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| `SELECT * FROM <table>` | Retrieve all rows from a table |
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| `UPDATE <table> SET <column_1> = <value_1> WHERE <column_2> = <value_2>` | Update rows in a table |
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| `DELETE FROM <table> WHERE <column> = <value>` | Delete rows from a table |
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Data Query Language (DQL)
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-------------------------
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| Command | Description |
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| --- | --- |
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| `SELECT <column_1>, <column_2> FROM <table>` | Retrieve specific columns from a table |
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| `SELECT * FROM <table> WHERE <column> = VALUE` | Retrieve rows that match a condition |
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| `SELECT * FROM <table> ORDER BY <column>` | Retrieve rows sorted by a column |
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| `SELECT * FROM <table> LIMIT N` | Retrieve the first N rows from a table |
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| `SELECT * FROM <table> OFFSET N` | Retrieve rows starting from the Nth row |
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| `SELECT * FROM <table> JOIN <table_2> ON <table_1>.<column_1> = <table_2>.<column_2>` | Retrieve rows from two tables that match a condition |
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| `SELECT * FROM <table> UNION SELECT * FROM <table_2>` | Retrieve rows from two tables without duplicates |
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| `SELECT * FROM <table> GROUP BY <column>` | Group rows that have the same value in a column |
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| `SELECT * FROM <table> HAVING COUNT(<column>) > N` | Filter grouped rows that have more than N rows |
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| `SELECT * FROM <table> WHERE <column> IN (<value_1>, <value_2>)` | Retrieve rows where a column value matches any value in a list |
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| `SELECT * FROM <table> WHERE <column> BETWEEN <value_1> AND <value_2>` | Retrieve rows where a column value is within a range |
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| `SELECT * FROM <table> WHERE <column> LIKE '<value>%'` | Retrieve rows where a column value matches a pattern |
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| `SELECT * FROM <table> WHERE <column> IS NULL` | Retrieve rows where a column value is NULL |
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| `SELECT * FROM <table> WHERE <column> IS NOT NULL` | Retrieve rows where a column value is not NULL |
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Data Control Language (DCL)
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| Command | Description |
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| --- | --- |
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| `GRANT PERMISSIONS ON <table> TO <user>` | Grant permissions to a user |
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| `REVOKE PERMISSIONS ON <table> FROM <user>` | Revoke permissions from a user |
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Transaction Control Language (TCL)
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----------------------------------
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| Command | Description |
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| --- | --- |
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| `BEGIN TRANSACTION` | Start a new transaction |
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| `COMMIT` | Save changes to the database |
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| `ROLLBACK` | Discard changes to the database |
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| `SAVEPOINT <savepoint>` | Create a savepoint in a transaction |
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| `ROLLBACK TO SAVEPOINT <savepoint>` | Rollback to a savepoint in a transaction |
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| `RELEASE SAVEPOINT <savepoint>` | Remove a savepoint in a transaction |
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System Commands
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| Command | Description |
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| --- | --- |
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| `SHOW DATABASES` | List all databases |
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| `SHOW TABLES` | List all tables in the current database |
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| `SHOW COLUMNS FROM <table>` | List all columns in a table |
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| `SHOW INDEXES FROM <table>` | List all indexes in a table |
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| `SHOW CREATE TABLE <table>` | Show the SQL statement that creates a table |
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| `DESCRIBE <table>` | Show the structure of a table |
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| `EXPLAIN SELECT * FROM <table>` | Show the execution plan of a query |
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| `SET autocommit = 0` | Disable autocommit mode |
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| `SET autocommit = 1` | Enable autocommit mode |
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| `SET FOREIGN_KEY_CHECKS = 0` | Disable foreign key checks |
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User Commands
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| Command | Description |
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| --- | --- |
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| `CREATE <user> '<user>'@'<host>' IDENTIFIED BY '<password>'` | Create a new user |
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| `DROP <user> '<user>'@'<host>'` | Delete a user |
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| `ALTER <user> '<user>'@'<host>' IDENTIFIED BY '<password>'` | Change password for a user |
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| `GRANT ALL PRIVILEGES ON <db> TO '<user>'@'<host>'` | Grant all privileges to a user |
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| `REVOKE ALL PRIVILEGES ON <db> FROM '<user>'@'<host>'` | Revoke all privileges from a user |
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| `FLUSH PRIVILEGES` | Reload privileges from the grant tables | |