SQL Quick Reference (Cheat Sheet) 📄

Mentor's Note: Keep this page bookmarked! It contains the "Formula" for every major SQL command we've learned. 💡

---

🏗️ Structure (DDL)

Action	Syntax
Create Table	CREATE TABLE table (col type, ...);
Add Column	ALTER TABLE table ADD col type;
Drop Column	ALTER TABLE table DROP COLUMN col;
Delete Table	DROP TABLE table;
Clear Table	TRUNCATE TABLE table;

---

📝 Data Operations (DML)

Action	Syntax
Fetch All	SELECT * FROM table;
Add Row	INSERT INTO table (cols) VALUES (vals);
Modify Row	UPDATE table SET col = val WHERE condition;
Remove Row	DELETE FROM table WHERE condition;

---

🔍 Filtering & Sorting

Filter	Logic
Range	WHERE salary BETWEEN 1000 AND 5000
Set	WHERE city IN ('Surat', 'Mumbai')
Pattern	WHERE name LIKE 'A%'
NULLs	WHERE email IS NULL
Sort	`ORDER BY name ASC

---

🕸️ Joins

Join Type	Description
INNER JOIN	Match in BOTH tables. ✅
LEFT JOIN	ALL from Left + Matches from Right. 👈
FULL JOIN	EVERYTHING from both. 🌕

---

📊 Aggregates

• COUNT(*): Total Rows.
• SUM(col): Total Sum.
• AVG(col): Mean.
• MIN/MAX: Smallest/Largest.

---

💡 Syntax Hierarchy

1. SELECT
2. FROM
3. WHERE
4. GROUP BY
5. HAVING
6. ORDER BY

---

📈 Learning Path

• ← Back: Reference Hub
• Next: Quiz & Practice →