Can I do this? I'm not getting any output, but i'm also not getting any PHP errors!!!
if ($brand=="all") {$sqlall =WHERE Is_Active = 1 ORDER BY prio;}
should be
$sqlall="where Is_Active = 1 ORDER BY prio";
else { $sqlall WHERE Is_Active = 1 AND subCat=$brand ORDER BY prio}
should be
$sqlall=" WHERE Is_Active = 1 AND subCat=$brand ORDER BY prio";
$strSQL = "SELECT SKU,Nom FROM Produit $sqlall";
You are missing some quotes