[How To?] Generate spreadsheet join date & first post date

[Puppyite]

How can I automatically generate a spreadsheet based on my forum’s membership with these columns:

• Member
  
• Join Date
  
• First Post
  

What I am after is this:
Cell 1 of row 1 of column 1 would contain the member name.
Cell 2 of row 1 of column 2 would contain the member join date.
Cell 3 of row 1 of column 3 would contain the member first post date.

If anyone can suggest a better place to post this I will ask mod to move it. Thank you for your help.

[.m.]

user name and join date can be easily exported from your server's database manager (eg. phpMyAdmin)
getting the date of first post appears to be a difficult task.
...................
Edit : below SQL Query should work and result can be exported to a CSV file

SELECT u.uid, u.username, FROM_UNIXTIME( u.regdate ) AS  "Join Date", FROM_UNIXTIME( m.dateline ) AS  "First Post"
FROM  `mybb_users` AS u

INNER JOIN (
SELECT uid, dateline
FROM  `mybb_posts` 
GROUP BY uid
ORDER BY dateline
)m ON u.uid = m.uid
ORDER BY uid ASC 

[.m.]

php file is attached with above content. can be used from forum directory where global.php file exists.

  joindate.php (Size: 457 bytes / Downloads: 112)