SQL Challenges · THE GREAT DUCK MIGRATION!
Cross-Training Champions
Difficulty: medium
Captain Cosmos floats down with satellite weather data and route projections. The migration path has drastically changed due to climate anomalies! Well encounter flooded mountain passes requiring both swimming through valleys AND flying over peaks in rapid succession. Find athletes whove competed in BOTH swimming and flying_speed events - these rare amphibious champions can seamlessly transition between water and air. Sum their identification codes for the elite cross-training squadron registry!
Your task
Return the sum of SSNs for all ducks who have competed in BOTH swimming and flying_speed events. You will be working with the `duck_athletes` and `performance_records` tables to find cross-training athletes.