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Use this to query, manipulate, and manage databases like a pro.
1️⃣ Basics
SELECT: Retrieve data
SELECT FROM employees;
WHERE: Filter data
SELECT FROM employees WHERE age > 30;
ORDER BY: Sort results
SELECT FROM employees ORDER BY salary DESC;
LIMIT: Restrict rows
SELECT FROM employees LIMIT 5;
2️⃣ Filtering
AND, OR, NOT
SELECT FROM products WHERE price > 100 AND stock < 50;
IN, BETWEEN, LIKE
SELECT FROM users WHERE city IN ('NY', 'LA');
SELECT FROM orders WHERE date BETWEEN '2024-01-01' AND '2024-12-31';
SELECT FROM customers WHERE name LIKE 'A%';
3️⃣ Aggregations
COUNT(), SUM(), AVG(), MIN(), MAX()
SELECT COUNT() FROM orders; SELECT AVG(salary) FROM employees;
GROUP BY, HAVING
SELECT department, AVG(salary) FROM employees GROUP BY department HAVING AVG(salary) > 50000;
4️⃣ Joins
INNER JOIN
SELECT e.name, d.name FROM employees e INNER JOIN departments d ON e.dept_id = d.id;
LEFT JOIN, RIGHT JOIN, FULL OUTER JOIN
SELECT FROM orders o LEFT JOIN customers c ON o.customer_id = c.id;
5️⃣ Subqueries
In WHERE clause
SELECT FROM employees WHERE dept_id IN (SELECT id FROM departments WHERE name = 'HR');
In FROM clause
SELECT avg_salary FROM (SELECT AVG(salary) AS avg_salary FROM employees) AS sub;
6️⃣ Modifying Data
INSERT
INSERT INTO users (name, email) VALUES ('John Doe', '[email protected]');
UPDATE
UPDATE employees SET salary = salary 1.1 WHERE performance = 'Excellent';
DELETE
DELETE FROM users WHERE inactive = TRUE;
7️⃣ Table Management
CREATE TABLE
CREATE TABLE products (id INT PRIMARY KEY, name VARCHAR(100), price DECIMAL(10,2));
ALTER TABLE
ALTER TABLE users ADD COLUMN age INT;
DROP TABLE
DROP TABLE old_data;
8️⃣ Constraints
PRIMARY KEY, FOREIGN KEY, NOT NULL, UNIQUE, DEFAULT
CREATE TABLE orders (id INT PRIMARY KEY, user_id INT, FOREIGN KEY (user_id) REFERENCES users(id));
9️⃣ Other Essentials
UNION, INTERSECT, EXCEPT
CASE WHEN: Conditional logic
SELECT name, CASE WHEN salary > 50000 THEN 'High' ELSE 'Low' END AS salary_level FROM employees;
INDEX: Speed up queries
CREATE INDEX idx_name ON employees(name);
You Should Know:
Essential SQL Commands for Cybersecurity & IT
Database Enumeration (Penetration Testing)
-- List all tables in a database (MySQL) SELECT table_name FROM information_schema.tables WHERE table_schema = 'database_name'; -- Extract column names (PostgreSQL) SELECT column_name FROM information_schema.columns WHERE table_name = 'users';
SQL Injection Exploitation
-- Basic UNION-based injection ' UNION SELECT username, password FROM users-- -- Blind SQLi (Time-based) ' OR IF(1=1, SLEEP(5), 0)--
Database Backup & Recovery
MySQL dump mysqldump -u root -p database_name > backup.sql PostgreSQL dump pg_dump -U postgres database_name > backup.sql
Linux Database Management
Start MySQL service sudo systemctl start mysql Secure PostgreSQL access sudo nano /etc/postgresql/14/main/pg_hba.conf
Windows SQL Server Commands
Check SQL Server status Get-Service -Name "MSSQLSERVER" Backup SQL database BACKUP DATABASE dbname TO DISK = 'C:\backup.bak';
What Undercode Say:
SQL is a fundamental skill for cybersecurity professionals, database administrators, and developers. Mastering these commands enhances efficiency in:
– Penetration Testing (SQLi, DB Enumeration)
– Incident Response (Log Analysis, DB Forensics)
– DevOps & Automation (Scripting DB Tasks)
Pro Tip: Always sanitize inputs to prevent SQL injection. Use prepared statements:
Python (SQLite Example)
cursor.execute("SELECT FROM users WHERE username = ?", (user_input,))
Expected Output:
A well-structured SQL cheatsheet with practical cybersecurity applications, including database security best practices and exploitation techniques.
Prediction:
SQL will remain a critical skill as databases evolve, with NoSQL and AI-driven query optimization gaining traction. Ethical hackers must adapt to new database security challenges.
References:
Reported By: Surajdevx Sql – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
