技术请求：对Products表中单价超10美元的商品应用50%折扣

Got it, let's break this down into two common scenarios you might need—either just viewing the discounted prices without modifying your data, or permanently updating the prices in the table.

1. View Discounted Prices (No Data Modification) #

If you just want to preview what the discounted prices would look like without altering the actual table data, use a SELECT query to calculate the discounted value on the fly:

SELECT 
    ProductID,
    ProductName,
    Price AS OriginalPrice,
    Price * 0.5 AS DiscountedPrice
FROM Products
WHERE Price > 10;

This query will return:

• The product's ID and name
• Its original price (labeled clearly as OriginalPrice)
• The 50% discounted price (labeled as DiscountedPrice)
  Only products with a price greater than $10 will show up in the results.

2. Permanently Update Prices in the Table #

If you need to actually modify the Price column in the Products table to lock in the 50% discount, use an UPDATE statement. Critical note: Always verify your target rows first with a SELECT query to avoid accidental mass updates!

First, run the SELECT query above to confirm exactly which products will be affected. Then execute the update:

UPDATE Products
SET Price = Price * 0.5
WHERE Price > 10;

This will multiply the Price value by 0.5 (a straight 50% cut) for every row where the original price is over $10. Skip the WHERE clause at your peril—without it, every single product in the table would get the discount, which is almost never what you want.

内容的提问来源于stack exchange，提问作者Simba