Oracle 递归查询

select a.accountcodeid, a.accountcode, a.accountcodename,
       SYS_CONNECT_BY_PATH(a.accountcodename, '') as fullname, a.parentcodeid, level
  from fm_accountcode a
 where a.accountcodeid >= 10000
 start with a.parentcodeid is null
connect by prior a.accountcodeid = a.parentcodeid;

select a.accountcodeid, a.accountcode, a.accountcodename,
       SYS_CONNECT_BY_PATH(a.accountcodename, '') as fullname,
       a.parentcodeid
  from fm_accountcode a
 where a.accountcodeid > 10000
   and connect_by_isleaf = 1
 start with a.parentcodeid is null
connect by prior a.accountcodeid = a.parentcodeid;

oracle 中递归查询，对树型结构数据相当有用。

二者区别：上，所有数据，包含结构；下，所有末节点，包含结构，具体参见Oracle Document 11g。