update a set last_age=
(select b.age from a b where a.id!=b.id and ok is not null and ok !=0 and a.age>b.age
rownum=1 order by a.age-b.age )

------解决方案--------------------
排了序了更新，
判断-1跟当前的差值跟+1跟当前的差值就行了

------解决方案--------------------
那3岁的呢  没得更小的了 不更新？

------解决方案--------------------
探讨

SQL code


update a set last_age=
(select b.age from a b where a.id!=b.id and ok is not null and ok !=0 and a.age>b.age
rownum=1 order by a.age-b.age )