[SQL]문법정리9(character)

SELECT u.user_id ,
u.email ,
SUBSTRING_INDEX(email, '@',-1)
FROM users u ;

SELECT o.order_no ,
o.created_at,
SUBSTRING(o.created_at,1,10) as Date
FROM orders o ;

SELECT SUBSTRING(o.created_at,1,10) as Date,
COUNT(*)
FROM orders o
group by Date;

SELECT o.order_no ,
o.created_at,
SUBSTRING(o.created_at,12,8) as time
FROM orders o ;