Click-Through Rate by Campaign

For each campaign return the click-through rate (total clicks / total impressions) as a percentage rounded to two decimals. Order by rate descending.

Table schema

Ads(id INT PRIMARY KEY, campaign VARCHAR(10), impressions INT, clicks INT)

Sample data

id | campaign | impressions | clicks
1 | A | 1000 | 50
2 | B | 500 | 40
3 | A | 500 | 10