# Crunching the Cloud

THE CLOUD EXPEDITION! · level 6 · chapter 2

Dr. Velocity makes an early cameo, slamming open the door with a clipboard. 'Enough peeking at 10 rows — let's see what this cloud can REALLY do!' She taps a chart showing migration routes across continents. 'Aggregate the ENTIRE global migrations table. No LIMIT. Let MotherDuck flex.' Time for <span class='feature-highlight'>Cloud Aggregations</span> — summarizing large cloud datasets with GROUP BY.

## Task

Which ponds send out the most migration flocks? Summarize by origin pond — show the <b>origin_pond</b>, flight count (<b>total_flights</b>), and average flock size rounded to 2 decimals (<b>avg_flock_size</b>). Busiest ponds first. Table: `dbquacks_cloud_expedition.global_migrations` (MotherDuck).

## Hint

Remember ROUND for controlling decimal places in your averages

## Expected result

Rows with origin_pond, total_flights, and avg_flock_size — one per pond, ordered by most flights

## Tables

### `lake_visits` (500 rows)

| column | type |
| --- | --- |
| visit_id | BIGINT |
| duck_id | BIGINT |
| destination_pond | VARCHAR |
| visit_date | DATE |
| purpose | VARCHAR |

### `pondville_events` (50 rows)

| column | type |
| --- | --- |
| event_id | BIGINT |
| event_name | VARCHAR |
| event_date | DATE |
| organizer_id | BIGINT |
| location | VARCHAR |
| attendee_count | BIGINT |

### `pondville_residents` (100 rows)

| column | type |
| --- | --- |
| duck_id | BIGINT |
| name | VARCHAR |
| species | VARCHAR |
| home_pond | VARCHAR |
| age | BIGINT |
| occupation | VARCHAR |
| joined_date | DATE |

### `dbquacks_cloud_expedition.global_migrations`

A table in a MotherDuck share; its columns are not listed here.

## Data

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

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

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

This level also queries MotherDuck shares, which need a MotherDuck token. On the page, the editor asks for one.

Play it in the browser: https://dbquacks.com/motherduck/6

## Reference

https://duckdb.org/docs/stable/sql/functions/aggregates