ORACLE (CASE, SUBSTR)

오라클 SUBSTR 와 CASE문 사용법 입니다.

SELECT
  ID,
  NAME,
  SUBSTR(NAME, 1,2) NAME1,
  SUBSTR(NAME, 3,2) NAME2,
  WRITER,
  PRICE,
  CASE --IF-ELSE
    WHEN PRICE < 301 THEN PRICE
    WHEN PRICE < 601 THEN (PRICE - PRICE*10/100)
    WHEN PRICE < 901 THEN (PRICE - PRICE*20/100)
      ELSE PRICE
    END as DISCOUNT_PRICE,
  CASE PRICE --SWITCH
    WHEN 300 THEN PRICE
    WHEN 600 THEN (PRICE*10/100)
    WHEN 900 THEN (PRICE*20/100)
      ELSE PRICE
    END as DISCOUNT,
  GENRE,
  PUBLISHER,
  CNT
FROM BOOKS;