How to redirect non www to www? [closed]

Just below

RewriteEngine On
RewriteBase /

add

RewriteCond %{HTTP_HOST} ^example.com$ [NC]
RewriteRule (.*) http://www.example.com/$1 [R=301,L] 

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)