上次在线（15分钟前）

I try to do mysql query, I want to load (or count) members, that was 15 ago online. I try:

SELECT COUNT(uid) FROM user WHERE `lastlogin` >  ".time()." - 3600;

But it doesn't work, i receive all membert list. Where I have made a mistake? Can you, please, help me?

Why not use the database's own time:

SELECT COUNT(uid) FROM user WHERE `lastlogin` >= DATE_SUB(NOW(), INTERVAL 15 MINUTE)