## Bug description

*Please describe.*  
- some datapoints show 0 but people will appear in modal

*If this affects the front-end, screenshots would be of great help.*  

## Expected behavior
- amount of people and datapoint should be the same


## How to reproduce

1. demo data clickhouse instance
2. go to retention trends for a day with some people


## Environment

- [ ] PostHog Cloud
- [ ] self-hosted PostHog, version/commit: _please provide_

## Additional context



#### *Thank you* for your bug report – we love squashing them!

ee/clickhouse/sql/retention/people_in_period.py
RETENTION_PEOPLE_PER_PERIOD_SQL = """
SELECT toString(person_id), count(person_id) appearance_count, groupArray(intervals_from_base) appearances FROM (
    SELECT DISTINCT
        datediff(%(period)s, {trunc_func}(toDateTime(%(start_date)s)), reference_event.event_date) as base_interval,
        datediff(%(period)s, reference_event.event_date, {trunc_func}(toDateTime(event_date))) as intervals_from_base,
        event.person_id
    FROM (
        SELECT 
        timestamp AS event_date,
        pdi.person_id as person_id,