convert original URL to friendly URL via mod-rewrite - .htaccess

Question

I have 2 type of url in my page.
1- http://www.example.com/index.php?id=12
I want always this:
http://www.example.com/12
But for anything else like:
2- http://www.example.com/index.php?id=12&id2=123&asd=qwe&svd=sdf...
I want it with no change:
http://www.example.com/?id=12&id2=123&asd=qwe&svd=sdf...
SO I want only redirect for http://www.example.com/index.php?id=12
I try this
RewriteCond %{THE_REQUEST} ^GET\ /(.*/)?(?:index\.php)?\?id=([^\s&]+) [NC]
RewriteRule ^ /%1%2? [R=301,L]
it works only for first (http://www.example.com/index.php?id=12)
but for second,it redirect to (http://www.example.com/***)
I read in stackoveflow I must use [QSA,L]
So I try this:
RewriteCond %{THE_REQUEST} ^GET\ /(.*/)?(?:index\.php)?\?id=([^\s&]+) [NC]
RewriteRule ^ /%1%2? [QSA,L]
But I got 500 error (Internal Server Error)
this is my complete code:
RewriteEngine On
RewriteBase /
RewriteCond %{THE_REQUEST} ^GET.*index\.php [NC]
RewriteRule (.*?)index\.php/*(.*) /$1$2 [R=301,NE,L]
RewriteCond %{HTTP_HOST} !^$
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteCond %{HTTPS}s ^on(s)|
RewriteRule ^ http%1://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
RewriteCond %{THE_REQUEST} ^GET\ /(.*/)?(?:index\.php)?\?id=([^\s&]+) [NC]
RewriteRule ^ /%1%2? [R=301,L]
---EDIT ---
I could do it with this
RewriteRule ^index.php/([^/]+)/?([^/]*) /index.php?id=$1 [NC]
for example www.example.com/123 works!
but www.example.com/index.php?id=123 not redirect to www.example.com/12

Answer 1

To convert http://example.com/index.php?id=foo to http://example.com/foo you can use the following rules in root/.htaccesso :
RewriteEngine on
#1)Redirect "/index.php?id=foo" to "/foo"#
RewriteCond %{THE_REQUEST} /(?:index\.php)?\?id=([^\s&]+)\sHTTP [NC]
RewriteRule ^ /%1? [L,R]
#2)The rule bellow will internally map "/foo" to "/index.php?id=foo"#
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^/]+)/?$ /index.php?id=$1 [L]
[Tested] This works on my apache server.