写一段oracle计算毛利率的sql并进行分组

Sure, I can help you with that! Here's a sample SQL statement that calculates gross profit margin and groups the results by product category:

SELECT category,
       SUM(sales) AS total_sales,
       SUM(costs) AS total_costs,
       (SUM(sales) - SUM(costs)) / SUM(sales) AS gross_profit_margin
FROM sales_data
GROUP BY category;

In this example, we assume that the sales data is stored in a table called "sales_data" and contains columns for product categories, sales revenue, and costs. The SQL statement first calculates the total sales and costs for each category using the SUM function. Then it calculates the gross profit margin as the difference between sales and costs, divided by sales. Finally, it groups the results by category using the GROUP BY clause.

I hope that helps! Let me know if you have any other questions.