How to set php htaccess options to a readable path?

Question

PHP

Good morning everyone!
Paths changed on the site:
/dir/?subdir=123
to
/dir/subdir123
But the following line in .htaccess doesn't work:

RewriteRule ^dir/\?subdir=(.+)$ dir/subdir$1 [R=301,L]

Please tell me where is the mistake.

Answer 1

RewriteCond %{QUERY_STRING} ^subdir=([0-9]*)$
RewriteRule ^dir$ /dir/subdir/%1 [R=301,L]
Probably something like that.

Answer 2

query string is not parsed