[SQL 문법] INNER JOIN + ON

두 테이블의 교집합을 찾는 JOIN

모든 'customer'의 'payment' amount,payment_date를 확인하기

SELECT 
	C.customer_id ,C.first_name 
	,C.last_name ,C.email
	,P.amount ,P.payment_date 
FROM customer c
INNER JOIN payment p 
ON C.customer_id =P.customer_id ;

 

그 중 id=3인 사람의 내역 확인하기

SELECT 
	c.customer_id ,c.first_name 
	,c.last_name , c.email 
	,p.amount ,p.payment_date 
FROM customer c
INNER JOIN payment p 
ON c.customer_id = p.customer_id 
WHERE c.customer_id  = 3 ;

 

고객의 payment data에 담당한 staff 이름도 같이 표시하기

SELECT
	c.customer_id ,c.first_name 
	,c.last_name ,c.email 
	,p.amount ,p.payment_date 
	,s.first_name AS S_first_name
	,s.last_name  AS S_last_name
FROM customer c 
INNER JOIN payment p
ON c.customer_id = p.customer_id 
INNER JOIN staff s 
ON p.staff_id = s.staff_id ;