SQL - Intento alcanzar el OUTPUT

select

    employee, min(fecha), max(fecha)

from

    (select

         t.*,

         lag(motive) over (partition by employee order by fecha) as prev_motive,

         lead(motive) over (partition by employee order by fecha) as next_motive,

         sum(case when motive = 'B' then 1 else 0 end) over (partition by employee order by fecha) as num_b

     from t) t

where

    motive = 'B'

    and (prev_motive <> 'B' or prev_motive is null)

    and (next_motive <> 'B' or next_motive is null)

group by

    employee, num_b;

select

    employee, min(fecha), max(fecha)

from

    (select

         t.*,

         lag(motive) over (partition by employee order by fecha) as prev_motive,

         lead(motive) over (partition by employee order by fecha) as next_motive,

         sum(case when motive = 'B' then 1 else 0 end) over (partition by employee order by fecha) as num_b

     from t) t

where

    motive = 'B'

    and (prev_motive <> 'B')

    and (next_motive <> 'B')

group by

    employee, num_b;