oracle中 connect by prior 递归算法,connect_by_root,sys_connect_by_path,connect_by_isleaf,CONNECT_BY_ISCYC
withtblas( select'A'asparent_cd,'C'aschild_cdfromdual unionall select'A'asparent_cd,'D'aschild_cdfromdual unionall select'C'asparent_cd,'B'aschild_cdfromdual unionall select'D'asparen