Views & Sequences

 1-- Create a view
 2CREATE VIEW active_users AS
 3SELECT id, name, email FROM users WHERE active = true;
 4
 5-- Query the view like a table
 6SELECT * FROM active_users;
 7
 8-- Create only if it doesn't exist
 9CREATE VIEW IF NOT EXISTS expensive_products AS
10SELECT * FROM products WHERE price > 100;
11
12-- Remove a view
13DROP VIEW active_users;
14DROP VIEW IF EXISTS expensive_products;

 1-- Create a sequence
 2CREATE SEQUENCE order_seq;
 3
 4-- Get next value
 5SELECT NEXTVAL('order_seq');  -- returns 1, 2, 3, ...
 6
 7-- Get current value (after NEXTVAL has been called)
 8SELECT CURRVAL('order_seq');
 9
10-- Use in INSERT
11INSERT INTO orders (id, product) VALUES (NEXTVAL('order_seq'), 'Widget');
12
13-- Remove a sequence
14DROP SEQUENCE order_seq;