Re: Help with SQL statement

[Roland Bouman]

Well, when you say that fewer than 2 is good too (meanin 1 or 0), this is the easiest and most straightforward:

select user_id
, max(connecttime)
from logins
group by user_id


This will give you the largest connecttime per user_id when for each user that has at least one login. When you need it for all users even if they never had a login this gives the equivalent result:

select u.user_id
, max(l.connecttime)
from users u
left join logins l
on u.user_id = l.user_id
group by u.user_id

so, max(connecttime) will be NULL for those users without logins.