使用递归子查询因子进行循环检测

Oracle SQL can do hierarchical queries since v2, using their proprietary CONNECT BY syntax. In their latest 11g release 2, they added recursive subquery factoring, also known as the recursive with clause. This is the ANSI standard, and if I understand correctly, this one has been implemented by other RDBMS vendors as well.Oracle SQL can do hierarchical queries since v2