How to htaccess 301 redirect pages with a question mark in the url - html

Question

I'm trying to redirect several pages that all have question marks in the URL.
I essentially want to redirect:
www.example.com/?attachment_id=456 to www.example.com
There's a ton of pages with differend id #s also.
I've tried a few things in htaccess with no luck..
Any ideas?
This is what I tried:
RewriteCond %{QUERY_STRING} ^attachment_id=[0-9]
RewriteRule ^/$ http://www.example.com/? [L,NC,R=301]

Answer 1

Why can't you do this? This code should redirect a URL like this www.example.com/?attachment_id=456
RewriteCond %{QUERY_STRING} ^attachment_id=[0-9]+
RewriteRule ^/?$ http://www.example.com/? [L,NC,R=301]
I made the / optional so that it can be used in Apache config or .htaccess. Also I kept the ? that you have in the redirect at the end of the RewriteRule to remove any query strings on redirect.

Answer 2

Your approach is next to perfect, just some minor corrections:
RewriteEngine on
RewriteCond %{QUERY_STRING} attachment_id=[0-9]+
RewriteRule ^/$ http://www.example.com/ [L,R=301]
The above is the version for the host configuration. note that you have to restart the http server after having made changes to the host configuration for them to get effective. To debug refer to the http servers error log file, especially at restart time.
If you have to rely on .htaccess style files, then the syntax for the rule itself must unfortunately be slightly different:
RewriteEngine on
RewriteCond %{QUERY_STRING} attachment_id=[0-9]+
RewriteRule ^$ http://www.example.com/ [L,R=301]
Such file has to be located in the main folder of the document root of the host. also the interpretation of such files must be enabled in the host configuration by means of the AllowOverride option.
In general you should always prefer the host configuration for such rules over .htaccess style files, but you need administrative access for that. .htaccess style files are notoriously error prone, hard to debug and really slow the server down.