一个需求实现的问题，用SQL怎么实现呢

Question

 

Answer 1

select t1.*,
       sum(t1.ad) over(order by t1.order_by)
  from (     
select t1.*,
       case when lag(t1.this_pagename) over(order by t1.order_by) = t1.this_pagename then 0 else 1 end ad
  from tab1 t1
) t1