Postgress SQL commands

//ORDER BY
SELECT * FROM person
ORDER BY age DESC;

//Distinct
SELECT DISTINCT country FROM person
ORDER BY country ASC;

//OFFSET
SELECT * FROM person
OFFSET 5 LIMIT 5

//IN
SELECT * FROM person
WHERE country IN('Brazil', 'Bolivia', 'Panama')

//COALESCE
SELECT COALESCE(email, 'email not provided') FROM person

//UNIQUE CONSTRAINT
ALTER TABLE person ADD CONSTRAINT unique_email_address UNIQUE (email);

//CHECK CONSTRAINT
ALTER TABLE person ADD CONSTRAINT gender_constraint CHECK (gender = 'Female' OR gender = 'Male');

//ON CONFLICT
ON CONFLICT (id) DO NOTHING
ON CONCLICT (id) DO UPDATE SET email = EXCLUDED.email