SQL WHERE Clause

SELECT * FROM users WHERE age > 18; # comparison
SELECT * FROM users WHERE country = 'USA'; # equality
SELECT * FROM users WHERE age <> 25; # not equal

SELECT * FROM users WHERE age > 18 AND country = 'USA'; # AND
SELECT * FROM users WHERE age < 18 OR age > 65; # OR
SELECT * FROM users WHERE NOT country = 'USA'; # NOT

SELECT * FROM products WHERE price BETWEEN 10 AND 100; # range (inclusive)

SELECT * FROM users WHERE country IN ('USA', 'UK', 'Canada'); # multiple values
SELECT * FROM users WHERE country NOT IN ('USA', 'UK'); # exclude values

SELECT * FROM users WHERE name LIKE 'J%'; # starts with J
SELECT * FROM users WHERE name LIKE '%son'; # ends with son
SELECT * FROM users WHERE name LIKE '%john%'; # contains john
SELECT * FROM users WHERE name LIKE 'J_n'; # _ matches one char

SELECT * FROM users WHERE email IS NULL; # null values
SELECT * FROM users WHERE email IS NOT NULL; # not null