10진수를 2진수로, 2진수를 10진수로 변환하기

[원쿼리맨]

10진수를 2진수로, 2진수를 10진수로 변환하기
(단, 소수점 이하 자리가 없다고 가정)


-- 10진수를 2진수로

SELECT     REPLACE (MAX (SYS_CONNECT_BY_PATH (bit, ',')), ',') bin
      FROM (SELECT     COUNT (*) OVER () - LEVEL + 1 level#,
                       DECODE (TRUNC (deci / POWER (2, LEVEL)),
                               ROUND (deci / POWER (2, LEVEL)), 0,
                               1
                              ) bit
                  FROM (SELECT 699 deci
                          FROM DUAL)
            CONNECT BY POWER (2, LEVEL - 1) <= deci)
START WITH level# = 1
CONNECT BY PRIOR level# = level# - 1


-- 2진수를 10진수로

SELECT     SUM (SUBSTR (bin, LEVEL, 1) * POWER (2, LENGTH (bin) - LEVEL)) deci
      FROM (SELECT 11101 bin
              FROM DUAL)
CONNECT BY LEVEL <= LENGTH (bin)