Maria Garcia

-- ROW_NUMBER: Unique sequential number
SELECT
  name,
  department,
  salary,
  ROW_NUMBER() OVER (ORDER BY salary DESC) as overall_rank,

-- Create basic index
CREATE INDEX idx_users_email ON users(email);

-- Unique index (enforces uniqueness)
CREATE UNIQUE INDEX idx_users_username ON users(username);

-- INNER JOIN: Only matching rows
SELECT
  users.name,
  orders.order_number,
  orders.total
FROM users