Redirection with HTACCESS including GET parameters - wordpress

Question

I have a specific .htaccess defined as is, in order to reroute all traffic from root folder to identical URL in a subfolder with exceptions on sub-domains.
Here's my file:
#RewriteEngine on
#RewriteRule ^(.*)$ http://www.mydomain.fr/blog/$1 [R=301,QSA]
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_HOST} !^joe\.mydomain\.fr$ [NC]
RewriteCond %{HTTP_HOST} !^lab\.mydomain\.fr$ [NC]
RewriteCond %{REQUEST_URI} !^joe(.*)
RewriteCond %{REQUEST_URI} !^lab(.*)
RedirectMatch ^/$ http://www.mydomain.fr/blog/
</IfModule>
This file does exactly what I want: when I input something like www.mydomain.fr/wp-admin for example, it will redirect to www.mydomain.fr/blog/wp-admin, but will exclude subdomains joe.mydomain.fr and lab.mydomain.fr from redirection.
However, what happens is that if I go to joe.mydomain.fr?test=1, the server will simply redirect me to joe.mydomain.fr but the GET parameter disappears.
How can I avoid that?
I tried replacing [NC] with [QSA] or [R=301,QSA], but I get an Internal Server Error.
Thanks.

Answer 1

After spending my day documenting about how .htaccess files actually work, I was finally able to solve my problem with the following file, inspired by the one from Abhishek Gurjar:
Options +FollowSymLinks
RewriteEngine On
RewriteBase /s
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_HOST} !^joe\.mydomain\.fr$ [NC]
RewriteCond %{HTTP_HOST} !^lab\.mydomain\.fr$ [NC]
RewriteCond %{HTTP_HOST} !^blog\.mydomain\.fr$ [NC]
RewriteCond %{REQUEST_URI} !/joe
RewriteCond %{REQUEST_URI} !/lab
RewriteRule ^(.*)$ http://www.mydomain.fr/blog/$1 [R=301]
</IfModule>
FYI, the 3 first lines are mandatory with my provider 1&1 apparently...
What I changed is the REQUEST_URI from being !^joe(.* ) and !^lab(.*) to !/joe and !/lab and then excluding the blog.mydomain.fr URL as well to avoid problems with blog.mydomain.fr/joe or blog.mydomain.fr/lab if ever one day I use them.
Finally, I had to redirect my sub-domains in my 1&1 client interface to the subfolders of my webspace instead of the URL in hard, meaning:
Instead of redirecting joe.mydomain.fr to http://www.mydomain.fr/joe, I redirect it to /www/joe/
That configuration now allows me to type in an URL such as joe.mydomain.fr?dnt=1 while getting redirected to http://www.mydomain.fr/joe?dnt=1 which is exactly what I wanted to do.
I hope this helps others.
Thanks for the help.