# The Incomplete Roster

THE GREAT DUCK MIGRATION! · challenge 25 · hard

> Coach Waddles flips through training rosters with growing concern. "We have four core disciplines - swimming, flying_speed, running, and diving. Most of our athletes have trained in all four, but some have gaps in their experience! I need to identify ducks who competed in exactly three sports. These athletes require targeted training in their missing discipline before we depart. Their near-complete skill sets make them valuable, but that one gap could be dangerous!"

## Task

Return the sum of SSNs for all ducks who have competed in exactly 3 different sports throughout their career. You will be working with `duck_athletes` and `performance_records` tables.

## Tables

### `performance_records` (800 rows)

| column | type |
| --- | --- |
| duck_id | BIGINT |
| sport | VARCHAR |
| score | DOUBLE |
| competition_date | DATE |

### `duck_athletes` (50 rows)

| column | type |
| --- | --- |
| id | BIGINT |
| ssn | BIGINT |
| name | VARCHAR |
| age | BIGINT |
| hometown | VARCHAR |

## Data

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

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

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

Play it in the browser: https://dbquacks.com/challenges/athletic/25

## Answer

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