zkuste toto:
$SQLquery = "SELECT * FROM albums WHERE price2 > 1 ORDER BY (price-price2)/price ASC";
nebo
$SQLquery = "SELECT * FROM albums WHERE price2 > 1 ORDER BY ((price-price2)/price) ASC";
zkuste toto:
$SQLquery = "SELECT * FROM albums WHERE price2 > 1 ORDER BY (price-price2)/price ASC";
nebo
$SQLquery = "SELECT * FROM albums WHERE price2 > 1 ORDER BY ((price-price2)/price) ASC";