connect by

遍历树结构

SELECT SWJGJC,
       CONNECT_BY_ROOT SWJGJC AS "root",
       CONNECT_BY_ISLEAF AS "isleaf",
       LEVEL,
       SYS_CONNECT_BY_PATH(SWJGJC, '/') AS "path"
  FROM DM_GY_SWJG_JH
 START WITH SWJG_DM = '23307000000'
CONNECT BY PRIOR SWJG_DM = SJSWJG_DM;

遍历特性

1. 生成 1 .. 10 序号

SELECT ROWNUM FROM DUAL CONNECT BY ROWNUM <= 10;

2. 把 16 进制数'abc'转换成十进制（遍历每个位数做处理）

SELECT SUM((CASE UPPER(SUBSTR('abc', ROWNUM, 1))
             WHEN 'A' THEN
              '10'
             WHEN 'B' THEN
              '11'
             WHEN 'C' THEN
              '12'
             WHEN 'D' THEN
              '13'
             WHEN 'E' THEN
              '14'
             WHEN 'F' THEN
              '15'
             ELSE
              SUBSTR('abc', ROWNUM, 1)
           END) * POWER(16, LENGTH('abc') - ROWNUM)) DATA
  FROM DUAL
CONNECT BY ROWNUM <= LENGTH('abc');