ORDER BY 练习的解决方案

1. SELECT id, occurred_at, total_amt_usd
   FROM orders
   ORDER BY occurred_at
   LIMIT 10;

2.

SELECT id, account_id, total_amt_usd
FROM orders
ORDER BY total_amt_usd DESC 
LIMIT 5;

3. SELECT id, account_id, total
   FROM orders
   ORDER BY total
   LIMIT 20;