Post #1899

SQL Cheat Sheet For Data Analysts📚✅ 1️⃣Basic Aggregates ⦁ SUM() – Adds up values: SELECT SUM(sales) FROM orders; ⦁ AVG() – Calculates average: SELECT AVG(score) FROM tests; ⦁ MIN() / MAX() – Smallest/largest value: SELECT MIN(age), MAX(age) FROM users; ⦁ COUNT() – Counts rows: SELECT COUNT(*) FROM customers; 2️⃣Conditional Logic ⦁ CASE WHEN – If/else logic: SELECT name, CASE WHEN score > 50 THEN 'Pass' ELSE 'Fail' END AS result FROM students; ⦁ COALESCE() – Returns first non-null: SELECT COALESCE(phone, 'N/A') FROM contacts; 3️⃣String Functions ⦁ LEFT(), RIGHT(), SUBSTRING() – Extract text: SELECT LEFT(name, 3) FROM employees; ⦁ LENGTH() – Counts characters: SELECT LENGTH(address) FROM users; ⦁ TRIM(), UPPER(), LOWER() – Clean/change case: SELECT TRIM(email), UPPER(city) FROM users; ⦁ CONCAT() – Combine text: SELECT CONCAT(first_name, ' ', last_name) FROM users; 4️⃣Lookup/Join ⦁ JOIN – Combine tables: SELECT o.order_id, c.name FROM orders o JOIN customers c ON o.customer_id = c.id; ⦁ IN / EXISTS – Check for values: SELECT * FROM products WHERE category_id IN (1,2,3); 5️⃣Date & Time ⦁ CURRENT_DATE, CURRENT_TIMESTAMP – Today/now: SELECT CURRENT_DATE; ⦁ EXTRACT() – Get year/month/day: SELECT EXTRACT(YEAR FROM order_date) FROM orders; ⦁ DATEDIFF() – Days between dates: SELECT DATEDIFF('2025-07-08', '2025-01-01'); 6️⃣Data Cleaning ⦁ DISTINCT – Unique values: SELECT DISTINCT city FROM customers; ⦁ REPLACE() – Replace text: SELECT REPLACE(email, '.com', '.org') FROM users; ⦁ NULLIF() – Set value to NULL if condition met: SELECT NULLIF(status, 'unknown') FROM orders; 7️⃣Advanced Functions ⦁ GROUP BY – Aggregate by group: SELECT department, COUNT(*) FROM employees GROUP BY department; ⦁ HAVING – Filter after aggregation: SELECT department, COUNT(*) FROM employees GROUP BY department HAVING COUNT(*) > 5; ⦁ WINDOW FUNCTIONS – Running totals, ranks: SELECT name, salary, RANK() OVER (ORDER BY salary DESC) FROM staff; 8️⃣Views & CTEs ⦁ VIEW – Save a query: CREATE VIEW top_customers AS SELECT * FROM customers WHERE spend > 1000; ⦁ CTE – Temporary result set: WITH high_sales AS ( SELECT * FROM sales WHERE amount > 1000 ) SELECT * FROM high_sales; Free Resources to learn SQL: https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v ENJOY LEARNING👍👍