The only SQL cheat sheet you need

10 queries you write every week

1. 01

   WHERE

   SELECT * FROM orders WHERE amount > 500;

2. 02

   ORDER BY + LIMIT

   SELECT * FROM orders ORDER BY amount DESC LIMIT 5;

3. 03

   GROUP BY

   SELECT city, COUNT(*) FROM users GROUP BY city;

4. 04

   HAVING

   SELECT city, COUNT(*) FROM users
   GROUP BY city HAVING COUNT(*) > 10;

5. 05

   JOIN

   SELECT * FROM orders o
   JOIN users u ON o.user_id = u.id;

6. 06

   DISTINCT

   SELECT DISTINCT city FROM users;

7. 07

   COALESCE

   SELECT COALESCE(phone, 'NA') FROM users;

8. 08

   CASE WHEN

   CASE WHEN amount > 1000 THEN 'High' ELSE 'Low' END

9. 09

   RANK()

   RANK() OVER (ORDER BY salary DESC)

10. 10

    Running total

    SUM(amount) OVER (ORDER BY order_date)

SQL: how do I …

1. 01

   Count unique customers

   COUNT(DISTINCT customer_id)

2. 02

   Find customers who never ordered

   LEFT JOIN orders o ON o.user_id = u.id
   WHERE o.id IS NULL

3. 03

   Find duplicate emails

   GROUP BY email HAVING COUNT(*) > 1

4. 04

   Get the 2nd highest salary

   DENSE_RANK() OVER (ORDER BY salary DESC)  -- keep rank 2

5. 05

   Top 3 per department

   ROW_NUMBER() OVER (PARTITION BY dept ORDER BY salary DESC) <= 3  -- filter in outer query

6. 06

   Previous month's value

   LAG(sales) OVER (ORDER BY month)

7. 07

   Month-on-month change

   sales - LAG(sales) OVER (ORDER BY month)

8. 08

   Search text in a column

   WHERE name LIKE '%kumar%'

9. 09

   Match a list of values

   WHERE city IN ('Pune', 'Indore')

10. 10

    Filter a date range

    WHERE dt >= '2026-01-01' AND dt < '2026-04-01'

11. 11

    Replace NULL with 0

    COALESCE(amount, 0)

12. 12

    Avoid divide by zero

    amount / NULLIF(qty, 0)

13. 13

    Pull the year from a date

    EXTRACT(YEAR FROM order_date)

14. 14

    Join two text columns

    CONCAT(first_name, ' ', last_name)

15. 15

    Stack two tables

    UNION ALL  -- keeps duplicates

16. 16

    Check if related rows exist

    WHERE EXISTS (SELECT 1 FROM ...)

17. 17

    Reuse a subquery

    WITH t AS (SELECT ...) SELECT * FROM t

18. 18

    Percent of total

    amount * 100.0 / SUM(amount) OVER ()

19. 19

    Round to 2 decimals

    ROUND(avg_price, 2)

20. 20

    Count with a condition

    SUM(CASE WHEN status = 'Paid' THEN 1 ELSE 0 END)

Window functions (RANK, ROW_NUMBER, LAG) can't go in WHERE. Wrap them in a subquery or CTE, then filter.

Now type them yourself

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