mysql -u username -p

SHOW DATABASES;

USE database_name;

SHOW TABLES;

DESCRIBE table_name;

SELECT VERSION();

CREATE DATABASE database_name;

DROP DATABASE database_name;

CREATE TABLE table_name (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    age INT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

DROP TABLE table_name;

ALTER TABLE table_name ADD column_name VARCHAR(255);

ALTER TABLE table_name MODIFY column_name INT NOT NULL;

ALTER TABLE table_name DROP COLUMN column_name;

INSERT INTO table_name (name, age) VALUES ('Alice', 25);

SELECT * FROM table_name;

SELECT name, age FROM table_name;

SELECT * FROM table_name WHERE age > 20;

SELECT * FROM table_name ORDER BY age DESC;

SELECT * FROM table_name LIMIT 5;

UPDATE table_name SET age = 26 WHERE name = 'Alice';

DELETE FROM table_name WHERE name = 'Alice';

SELECT users.name, orders.amount FROM users
INNER JOIN orders ON users.id = orders.user_id;

SELECT users.name, orders.amount FROM users
LEFT JOIN orders ON users.id = orders.user_id;

SELECT users.name, orders.amount FROM users
RIGHT JOIN orders ON users.id = orders.user_id;

CREATE INDEX index_name ON table_name(column_name);

DROP INDEX index_name ON table_name;

START TRANSACTION;
UPDATE accounts SET balance = balance - 100 WHERE id = 1;
UPDATE accounts SET balance = balance + 100 WHERE id = 2;
COMMIT;

CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'password';

GRANT ALL PRIVILEGES ON database_name.* TO 'newuser'@'localhost';

REVOKE ALL PRIVILEGES ON database_name.* FROM 'newuser'@'localhost';

DROP USER 'newuser'@'localhost';

mysqldump -u username -p database_name > backup.sql

mysql -u username -p database_name < backup.sql

COMMAND target_clause condition_clause;

Breakdown:

• COMMAND – Specifies the operation (e.g., SELECT, INSERT, UPDATE, DELETE, CREATE, ALTER, etc.)
• target_clause – Defines what the command acts upon (e.g., table name, column names)
• condition_clause (optional) – Adds constraints or filters using WHERE, ORDER BY, LIMIT, etc.