SQLを使用して列内の連続していない値の数をカウントするにはどうすればよいですか？

このようなものですか？

SQL> with test (name, day, srvc_inv) as
  2    (select 'bill', 1, 1 from dual union all
  3     select 'bill', 2, 1 from dual union all
  4     select 'bill', 3, 0 from dual union all
  5     select 'bill', 4, 0 from dual union all
  6     select 'bill', 5, 1 from dual union all
  7     select 'bill', 6, 0 from dual union all
  8     select 'susy', 1, 1 from dual union all
  9     select 'susy', 2, 0 from dual union all
 10     select 'susy', 3, 1 from dual union all
 11     select 'susy', 4, 0 from dual union all
 12     select 'susy', 5, 1 from dual
 13    ),
 14  inter as
 15    (select name, day, srvc_inv,
 16       nvl(lead(srvc_inv) over (partition by name order by day), 0) lsrvc
 17     from test
 18    )
 19  select name,
 20    sum(case when srvc_inv <> lsrvc and lsrvc = 0 then 1
 21             else 0
 22        end) grp
 23  from inter
 24  group by name;

NAME        GRP
---- ----------
bill          2
susy          3

SQL>