[SQL] UNION / COUNT / BETWEEN

<1>

SELECT games FROM olympics_athletes_events WHERE age = (SELECT max(age) FROM olympics_athletes_events) 
UNION 
SELECT games FROM olympics_athletes_events WHERE age = (SELECT min(age) FROM olympics_athletes_events);

 

 

<2>

 

select count(order_id) from shopify_orders;

 

 

 

<3>

SELECT worker_id, login_timestamp FROM worker_logins
WHERE login_timestamp BETWEEN '2021-12-13 00:00:00' AND '2021-12-19 23:59:59';

Just include 'login_timestamp' to check for correctness.

 

* Between Date

12/13과 12/19를 포함하고 싶다면 명시하는 쿼리에 포함해야한다. 즉, 이상과 이하인 격.