oracle prior

--先上结论 prior id=fid时，下一行列fid的值起始行列id的值
--可以用树形结构来标识，当 prior父节点id=子节点fid时，父节点在最上
--当prior子节点fid=父节点id，父节点在最下

select id,fid from tab1
start with id=100078
connect by id=prior fid

1    100078    100971
2    100971    100735
3    100735    -1

select id,fid from tab1
start with id=100971
connect by  prior fid=id

1    100971    100735
2    100735    -1

select id,fid from tab1
start with id=100971
connect by prior id=fid
1    100971    100735
2    196    100971
3    197    196
4    220    196