[Beginning SQL Server 2005 Programming] JOIN

1. JOIN : 두 테이블의 정보를 결합하여 하나의 결과 집합인 "가상" 테이블을 만드는 것

2. INNER JOIN
  1) 구문

SELECT <선택 목록>
FROM <첫 번째 테이블>
<조인 유형> <두번째 테이블>
    [ON <조인 조건>]

  2) 간단한 JOIN

SELECT p.ProductID, s.SupplierID, p.ProductName, s.CompanyName
FROM Products p
INNER JOIN Suppliers s
   ON p.SupplierID = s.SupplierID
WHERE p.ProductID < 4

  3) 복잡한 JOIN

SELECT au_lname + ', ' + au_fname AS "Author", t.title
FROM authors a
JOIN titleauthor ta
   ON a.au_id = ta.au_id
JOIN titles t
   ON t.title_id = ta.title_id

3. OUTER JOIN
  1) 구문

SELECT <SELECT 목록>
FROM <왼쪽 테이블>
<LEFT|RIGHT> [OUTER] JOIN <오른쪽 테이블>
    ON <조인조건>

  2) LEFT OUTER JOIN

SELECT discounttype, discount, s.stor_name
FROM discounts d
LEFT OUTER JOIN stores s
   ON d.stor_id = s.stor_id

Initial Customer 10.50 NULL
Volume Discount 6.70 NULL
Customer Discount 5.00 Bookbeat

  3) RIGHT OUTER JOIN

SELECT discounttype, discount, s.stor_name
FROM discounts d
RIGHT OUTER JOIN stores s
 ON d.stor_id = s.stor_id

※ 출처: Beginning SQL Server 2005 Programming