# The Elite Performers

THE CHRISTMAS HEIST! · challenge 9 · medium

> Detective Quacker paces the room. "Driving through blizzard conditions... something's not adding up. This doesn't feel like a criminal!" General Gander arrives with strategic analysis charts and tactical maps covering all districts. "Detective! I've been reviewing the case files. Strategic profiling requires comparative analysis! For EACH district separately, I need to identify the volunteer with the most deliveries. Some volunteers excel in multiple districts, others in just one. Here's the question: What is the TOTAL number of deliveries made by all volunteers who rank #1 in at least one district? Count ALL their deliveries across the entire town, not just where they're champions! This will help us understand who's truly committed to their work."

## Task

Find all volunteers who rank #1 (most deliveries) in at least one district, then count ALL their deliveries across the entire dataset. Use the `delivered_by` column in deliveries_log to identify volunteers. You will be working with `deliveries_log` and `duck_households` tables. Note: It's possible for the same volunteer (like duck_id 1) to rank #1 in multiple districts - this is expected and correct.

## Tables

### `deliveries_log` (10000 rows)

| column | type |
| --- | --- |
| delivery_id | INTEGER |
| household_id | INTEGER |
| delivered_by | INTEGER |
| delivery_time | TIMESTAMP |
| success | BOOLEAN |
| parent_delivery_id | INTEGER |
| delivery_metadata | JSON |

### `duck_households` (200 rows)

| column | type |
| --- | --- |
| household_id | INTEGER |
| address | VARCHAR |
| district | VARCHAR |
| latitude | DOUBLE |
| longitude | DOUBLE |
| household_size | INTEGER |
| income_level | VARCHAR |
| reported_missing | BOOLEAN |

## Data

The tables live in a DuckDB database: https://dbquacks.com/data/databases/christmas_local.duckdb

To query it outside the browser, attach it read-only:

```sql
ATTACH 'https://dbquacks.com/data/databases/christmas_local.duckdb' AS db (READ_ONLY);
USE db;
```

Play it in the browser: https://dbquacks.com/challenges/christmas/9

## Answer

The expected answer is not published. Submit on the page to have it checked.