Ok, I'm done:
This query is better:
INSERT INTO `comment` ( `importid` , `contentid` , `userid` , `date` , `name` , `title` , `comment` , `published` , `importparentid` , `component` , `importtable` )
SELECT f.`id` , `parentid` , `created_by` , `created` , u.name, `title` , `fulltext` , 1, 'parentid', 'com_content', 'yvcomment'
FROM `content` AS f
LEFT JOIN users AS u ON f.created_by = u.id
WHERE catid ='category id'
it also takes the name of the user.
P.S. I hope that you'll write a good review about my component
extensions.joomla.org/extensions/contact...icles-comments/12259