'how to redirect subdomain to main domain in cloudfare

my site has multiple subdomains. in which my main site is www.mysite.com And a subdomain is old.mysite.com . But for some technical trouble i have to use only www version. So I wants to redirect all (old.mysite.com) and i want to keep old.mysite.com query string to keep working on www version.

iam not great at cloudflare page rules. and its kinda made whole mess in my head. https://support.cloudflare.com/hc/en-us/articles/218411427



Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source