To remove website field from all comments and user profiles in a wordpress powered site you need to run the following mysql commands:
To Remove Website Field from User Profiles
First you need to login to the command prompt of your virtual private server. Then execute the following commands.
mysql -u root -p show databases; use dbname; show tables; describe tableprefix_users; select count(*) from tableprefix_users where user_url!=''; select user_url from tableprefix_users where user_url!=''; update tableprefix_users set user_url='' where user_url!='';
To Remove Website Field from Comments
show tables; describe tableprefix_comments; select count(*) from tableprefix_comments where comment_author_url!=''; select user_url from tableprefix_comments where comment_author_url!=''; update tableprefix_comments set comment_author_url='' where comment_author_url!='';