I have two data items: swap total and swap free. I created a trigger with condition:

{Custom Linux Memory Template:proc.meminfo.swaptotal.last()}>0 and (100*{Custom Linux Memory Template:proc.meminfo.swapfree.last()}/{Custom Linux Memory Template:proc.meminfo.swaptotal.last()})<10

At the systems with swap partition or swap file, it works fine, but at the systems where no swap, I got "Division by zero", but I expected that the trigger will not be up, because the first part of the contion ({Custom Linux Memory Template:proc.meminfo.swaptotal.last()}>0) is false!

In my opinion, there no meaning to calculate second part of the condition if the first part is false and "AND" will be lead to false in any case.