Regex for rewrite of subdomains (3 replies)

I want to rewrite subdomains by adding a separate server for subdomains as


server {
server_name domain.com
...
}
server {
server_name *.domain.com
}

but how I can I ass a rewrite rule int the second server to process subdomain requests as

keyword.domain.com/query=some to domain.com/script.php?query=some&sub=keyword