SQL Commands Cheatsheet

SQL Command Overview

Command	Category	Description
SELECT	DML	Retrieves data from a table.
INSERT	DML	Adds new records to a table.
UPDATE	DML	Modifies existing data in a table.
DELETE	DML	Removes data from a table.
CREATE TABLE	DDL	Creates a new table.
ALTER TABLE	DDL	Modifies the structure of an existing table.
DROP TABLE	DDL	Deletes an existing table and its data.
GRANT	DCL	Grants specific privileges to a user or role.
REVOKE	DCL	Revokes specific privileges from a user or role.
COMMIT	DML/DCL	Saves changes made through DML statements and ends a transaction (also related to DCL for transaction control).

DML (Data Manipulation Language):

1. SELECT – Retrieve data from a table.

• Syntax:
  sql SELECT column1, column2 FROM table_name WHERE condition;
• Example:
  sql SELECT product_name, price FROM products WHERE category = 'Electronics';

1. INSERT – Insert data into a table.

• Syntax:
  sql INSERT INTO table_name (column1, column2) VALUES (value1, value2);
• Example:
  sql INSERT INTO customers (customer_name, email) VALUES ('John Doe', 'john.doe@example.com');

1. UPDATE – Modify existing data in a table.

• Syntax:
  sql UPDATE table_name SET column1 = new_value WHERE condition;
• Example:
  sql UPDATE products SET price = 199.99 WHERE product_id = 101;

1. DELETE – Remove data from a table.

• Syntax:
  sql DELETE FROM table_name WHERE condition;
• Example:
  sql DELETE FROM customers WHERE customer_id = 3;

DDL (Data Definition Language):

5. CREATE TABLE – Create a new table.

• Syntax:
  sql CREATE TABLE table_name ( column1 datatype, column2 datatype, ... );
• Example:
  sql CREATE TABLE products ( product_id INT, product_name VARCHAR(255), price DECIMAL(10, 2) );

5. ALTER TABLE – Modify the structure of an existing table.

• Syntax:
  sql ALTER TABLE table_name ADD column_name datatype;
• Example:
  sql ALTER TABLE products ADD quantity INT;

5. DROP TABLE – Delete an existing table and its data.

• Syntax:
  sql DROP TABLE table_name;
• Example:
  sql DROP TABLE invoices;

DCL (Data Control Language):

8. GRANT – Provide specific privileges to a user or role.

• Syntax:
  sql GRANT privilege ON object TO user_or_role;
• Example:
  sql GRANT SELECT, INSERT ON products TO sales_team;

8. REVOKE – Revoke specific privileges from a user or role.

• Syntax:
  sql REVOKE privilege ON object FROM user_or_role;
• Example:
  sql REVOKE INSERT ON products FROM sales_team;

8. COMMIT – Save changes to the database.

• Syntax:
  sql COMMIT;
• Example:
  sql -- After executing a series of INSERT, UPDATE, or DELETE statements COMMIT;

This cheat sheet covers the basic SQL commands for data manipulation, definition, and control. Use these examples as a starting point for your SQL operations in a database environment.