workforce_query

select
    *,
    case
        when (x.direction != x.next_row_direction or x.next_row_direction is null)
            then extract(EPOCH from x.duration) * 1000
        else 0
    end as real_difference
from (
select
    workforce_entry.id,
    workforce_entry_direction.description,
    workforce_entry.workforce_entry_direction_id as direction,
    lead(workforce_entry_direction_id, 1, null) over (partition by person_id order by date_time) as next_row_direction,
    (lead(date_time, 1, now()) over (partition by person_id order by date_time) - workforce_entry.date_time)  as duration
from workforce_entry
inner join workforce_entry_direction
    on workforce_entry_direction.id =  workforce_entry.workforce_entry_direction_id
) as x
where x.description = 'IN';