select comment_id,comment_ip,comment_created_on,substring(comment_text,1,20) from mt_comment where comment_blog_id=57;

select comment_ip,count(*) as cnt,substring(comment_text,1,80) from mt_comment where comment_blog_id=57 group by comment_ip,comment_text order by cnt desc limit 100;

select comment_ip,substring(comment_text,1,100) from mt_comment where comment_blog_id=57 and comment_created_on > date_sub(now(),interval 1 day);

delete from mt_comment where comment_blog_id=57 and comment_text like ' <h1>Please%';
delete from mt_comment where comment_blog_id=57 and comment_text like 'Hi, You should check out <a href="http:/%';
delete from mt_comment where comment_blog_id=57 and comment_text like '%\<h1\>%';
delete from mt_comment where comment_blog_id=57 and comment_text like '%<a href=%';
delete from mt_comment where comment_blog_id=57 and comment_text like '%http://%' and comment_created_on > date_sub(now(),interval 90 day);