Try:

$query2  = "UPDATE `Stats` SET `Usage` = '$from'";


'Usage' is a reserved word in MySQL:

http://dev.mysql.com/doc/refman/5.0/en/reserved-words.html

Adding seconds to mysql DateTime via php
Observe the following parts of an electron transfer equation:





The first equation says Li with a small subscript 2, however the second one says Al with a coefficient 2 instead of $\ce{Al_2}$.

Can someone please explain this discrepancy and inconsistency I'm seeing? Why is Lithium in the first reaction written with a small 2, while in the second one Aluminium is written with a big 2? Why can't both of them be written in the same way? Does it matter? Is there a difference? How do I tell which one to use?
