I'll take a deep breath and approach this carefully. To find the latest return on assets (ROA) for NVIDIA, we need to:
1. Filter the `earnings` table to get the most recent fiscal year data for NVIDIA.
2. Filter for NVIDIA using its symbol.
3. Ensure we get the latest available data by ordering by date and limiting the results to 1.
4. Include the relevant fields: symbol, date, and return on assets.
Now I will generate the query:
{
  "sql": "SELECT symbol, date, returnOnAssets FROM `my_project.my_dataset.earnings` WHERE symbol = 'NVDA' ORDER BY date DESC LIMIT 1"
}