Well thanks for the discussion, I forgot that $_SESSION was actually stored server-side and not sent as _GET and _POST. I'll to redesign a lot of things! (Better posting implmentation yay!)

Welp, if you want to get some news about my battle against PHP, it seems my project is working nicely at the moment. I'm still working between refactors and database redisign, but it's still fine.
For the moment.

Yeah, on my phone the red looks black. But if I choose brighter colors, I think that'll make it ugly. I'll to remake my color swatches.
The R-A logo will change, it never looked in place with the blog anyway. One graphical change to do too. I don't know how it'll look after then.

If you want to help me more, I woul'd be glad. i'm far from having finished it! ^^


EDIT : With your class, Joins doens't work at all...
res = $sql->query("SELECT `B.bi, `B.bn`, `B.bs` ".
   "FROM `Blah B` LEFT JOIN `Ah_Blah` A ON A.bi = B.bi ".
        "WHERE A.ai = `%s`;", [$_SESSION['ui']]);it only works without `quoting`


EDIT : Nailed it
res = $sql->query("SELECT `B`.`bi`, `B`.`bn`, `B`.`bs` ".
   "FROM `Blah` B LEFT JOIN `Ah_Blah` A ON `A`.`bi` = `B`.`bi` ".
        "WHERE `A`.`ai` = %d;", [$_SESSION['ui']]);

As it is SQL you don't need to join, it doesn't care about line breaks and weird tabs

Explicit joins are preferable in sql though. Implicit joins can be slower.