It works for me:
#On rewrite
RewriteEngine On
# Allow any files or directories that exist to be displayed directly
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
# rewrite domain.com/username.php to username
RewriteRule ^([A-Za-z0-9_-]+)/?$ $1.php [NC,L]
RewriteRule ^([A-Za-z0-9_-]+)/([A-Za-z0-9]+)/?$ $1/$2.php [NC,L]
RewriteRule ^([A-Za-z0-9_-]+)/([A-Za-z0-9]+)/([A-Za-z0-9]+)/?$ $1/$2/$3.php [NC,L]
And more:
Look at my rewrite file for social portal like fb:
# allow only from ip range /8 /16 /24 /31
#Order deny,allow
#Deny from all
#Allow from 89.230.0.0/16
# On rewrite
RewriteEngine On
# [NC]- case-insensitive
# [L] - Last Rule , stop the rewriting process here
# [OR] = Or - If it matches this condition or the next
# [QSA] - Append query string to rewriting url
# [R] - redirect [R=301] move permanently, 302 - temporarily, 403 - Forbidden, 404 - Not Found, 410 - Gone
# fix folder redirect images and css js/images/css/media
RewriteRule ^.+?/((img|css|js|media|upload|posts)/.+)$ /$1 [L,R=301,NC]
# Allow any files or directories that exist to be displayed directly
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
# does not work on IIS windows server url rewrite when importing
# RewriteCond %[REQUEST_FILENAME] !-l
# rewrite example.xx/index.php na example.xx/
RewriteCond %{THE_REQUEST} ^.*/index\.php
RewriteRule ^(.*)index\.(php|html?)$ / [R=301,NC,L]
#portfolio rewrite folder rewrite
# RewriteRule ^([portfolio]+)/?$ /portfolio/index.php?id=$1 [NC,L]
# pretty url example.xx/id/post/number
# rewrite domain.com/username like twitter or facebook users
RewriteRule ^([A-za-z0-9_-]+)/?$ index.php?username=$1 [NC,L]
# domain.com/post/name
RewriteRule ^([A-Za-z0-9_-]+)/([A-Za-z0-9]+)/?$ profil.php?id=$1&menu=$2 [NC,L]
# domain.com/cat/post/id
RewriteRule ^([A-Za-z0-9_-]+)/([A-Za-z0-9]+)/([0-9]+)/?$ profil.php?id=$1&menu=$2&page=$3 [NC,L]
#RewriteRule ^([A-Za-z0-9_-]+)/(ustawienia)/?$ ustawienia.php?id=$1&menu=$2 [NC,L]
#RewriteRule ^([A-Za-z0-9_-]+)/(wpisy)/?$ profil0.php?id=$1&menu=$2 [QSA,NC,L]
#RewriteRule ^([A-Za-z0-9_-]+)/(fani)/?$ profil1.php?id=$1&menu=$2 [QSA,NC,L]
#RewriteRule ^([A-Za-z0-9_-]+)/(ogladasz)/?$ profil2.php?id=$1&menu=$2 [QSA,NC,L]
#RewriteRule ^([A-Za-z0-9_-]+)/(zdjecia)/?$ profil3.php?id=$1&menu=$2 [QSA,NC,L]
#RewriteRule ^([A-Za-z0-9_-]+)/(video)/?$ profil4.php?id=$1&menu=$2 [QSA,NC,L]
#RewriteRule ^([A-Za-z0-9_-]+)/(ulubione)/?$ profil5.php?id=$1&menu=$2 [QSA,NC,L]
#RewriteRule ^([A-Za-z0-9_-]+)/(wiadomosci)/?$ profil6.php?id=$1&menu=$2 [QSA,NC,L]
#RewriteRule ^([A-za-z0-9_-]+)/?$ profil.php?id=$1 [NC,L]
#RewriteRule ^([A-Za-z0-9_-]+)/([A-Za-z0-9]+)/?$ profil.php?id=$1&menu=$2 [NC,L]
#RewriteRule ^([A-Za-z0-9_-]+)/([A-Za-z0-9]+)/([A-Za-z0-9]+)/?$ index.php?id=$1&dir=$2&post=$3 [NC,L]
# Redirect all subdomains
# RewriteCond %{HTTP_HOST} ^(.*)\.breakermind\.com
# RewriteRule ^(.*)$ http://breakermind.com/$1 [R=301,QSA,NC,L]
# Redirect all subdomains
# RewriteCond %{HTTP_HOST} ^www.ns2.breakermind.com [NC]
# RewriteRule ^(.*)$ http://breakermind.com/$1 [R=301,QSA,NC,L]
# RewriteCond %{HTTP_HOST} ^ns2.breakermind.com [NC]
# RewriteRule ^(.*)$ http://breakermind.com/$1 [R=301,QSA,NC,L]
# Redirect from www. to non-www (unhash if need)
# RewriteCond %{HTTP_HOST} ^www.breakermind.com [NC]
# RewriteRule ^(.*)$ http://breakermind.com/$1 [R=301,QSA,NC,L]
# Redirect from http:// to https:// (from no-ssl to ssl)
#RewriteCond %{SERVER_PORT} 80
#RewriteRule ^(.*)$ https://breakermind.com/$1 [R=301,QSA,NC,L]
ErrorDocument 400 /er404.html
ErrorDocument 401 /er404.html
ErrorDocument 402 /er404.html
ErrorDocument 403 /er403.html
ErrorDocument 404 /er404.html
ErrorDocument 500 /er404.html
ErrorDocument 502 /er404.html
ErrorDocument 504 /er404.html
#RewriteEngin On
#RewriteCond %[REQUEST_FILENAME] !-d
#RewriteCond %[REQUEST_FILENAME] !-f
#RewriteCond %[REQUEST_FILENAME] !-l
#RewriteRule ^(.+)$ index.php?c=$1 [QSA,L]
#
# \w = [A-Za-z0-9_] \d = [0-9]
And here from my blog system:
Options +FollowSymLinks
RewriteEngine On
RewriteCond %{THE_REQUEST} ^.*/index\.php
RewriteRule ^(.*)index\.(php|html?)$ / [R=301,NC,L]
# category
RewriteRule ^category/?$ index.php?id=0&page=0 [NC,L]
RewriteRule ^category/([A-Za-z0-9]+)/?$ index.php?id=$1&page=0 [NC,L]
RewriteRule ^category/([A-Za-z0-9]+)/([0-9]+)/?$ index.php?id=$1&page=$2 [NC,L]
RewriteRule ^category/([A-Za-z0-9]+)/([0-9]+)/([A-Za-z0-9]+)/?$ index.php?id=$1&page=$2&title=$3 [NC,L]
# autor
RewriteRule ^autor/?$ index.php?id=0&page=0 [NC,L]
RewriteRule ^autor/([A-Za-z0-9]+)/?$ index.php?id=$1&page=0 [NC,L]
RewriteRule ^autor/([A-Za-z0-9]+)/([0-9]+)/?$ index.php?id=$1&page=$2 [NC,L]
# article, gallery, tags
RewriteRule ^article/([A-Za-z0-9]+)/?$ article.php?id=$1 [NC,L]
RewriteRule ^gallery/([A-Za-z0-9]+)/?$ gallery.php?id=$1 [NC,L]
RewriteRule ^tags/([A-Za-z0-9]+)/?$ tags.php?id=$1 [NC,L]
RewriteRule ^archive/([0-9]+)/([0-9]+)/?$ archive.php?year=$1&month=$2 [NC,L]
# custom page rewrite
RewriteRule ^page/([A-Za-z0-9]+)/?$ page.php?id=$1 [NC,L]
# fix folder redirect images and css js/images/css/media
RewriteRule ^.+?/((admin|img|css|js|media|upload|posts)/.+)$ /blog/$1 [L,R=301,NC]
# user or category user.php
# RewriteRule ^([A-Za-z0-9]+)/?$ index.php?user=$1 [NC,L]
# example
# RewriteRule ^([folder])/([category])/([A-Za-z0-9]+)/?$ index.php?id=$3&cat=$2 [NC,L]
showthread?id=XXRewriteRule can not match query strings. So that's probably why it's not working. What is your main goal?