Perform Conditional Updates on Multiple Rows

UPDATE products
SET 
    price = CASE 
        WHEN category = 'electronics' THEN price * 1.10 -- Increase by 10%
        WHEN category = 'books' THEN price * 0.90 -- Decrease by 10%
        ELSE price
    END,
    updated_at = NOW()
WHERE 
    stock_quantity > 0;

How it works: This SQL snippet demonstrates how to perform conditional updates on multiple rows using the `CASE` statement within an `UPDATE` query. It allows you to apply different modifications to the `price` column based on the `category` of each product, increasing prices for 'electronics' and decreasing them for 'books'. The `updated_at` column is also set, and the `WHERE` clause ensures only products in stock are considered, offering flexible and powerful bulk update capabilities for dynamic data management.