Cheat Sheets/SQL Cheat Sheet

database

SQL Cheat Sheet

Essential SQL queries reference

SQLDatabaseQueries

Basic Queries

Select

SELECT * FROM users;

Select all rows

Where

SELECT * FROM users WHERE age > 18;

Filter rows

Order By

SELECT * FROM users ORDER BY name ASC;

Sort results

Limit

SELECT * FROM users LIMIT 10;

Limit number of rows

Joins

INNER JOIN

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

Matching rows from both

LEFT JOIN

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

All from left, matching from right

RIGHT JOIN

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

All from right, matching from left

Aggregation

COUNT

SELECT COUNT(*) FROM users;

Count rows

SUM

SELECT SUM(amount) FROM orders;

Sum values

AVG

SELECT AVG(age) FROM users;

Average value

GROUP BY

SELECT dept, COUNT(*) FROM employees GROUP BY dept;

Group and aggregate

HAVING

SELECT dept, COUNT(*) FROM employees GROUP BY dept HAVING COUNT(*) > 5;

Filter after grouping