SQL Functions

SQL provides many built-in functions to help you manipulate and analyze data efficiently.

Aggregate Functions

COUNT

Count the number of rows:

SELECT COUNT(*) FROM books;

SUM

Calculate the total:

SELECT SUM(price) FROM books;

AVG

Calculate the average:

SELECT AVG(rating) FROM reviews;

String Functions

UPPER and LOWER

SELECT UPPER(first_name) FROM customers;
SELECT LOWER(email) FROM customers;

CONCAT

SELECT CONCAT(first_name, ' ', last_name) AS full_name
FROM authors;

Master these functions to become more efficient with SQL!