How to calculate 20% change within one hour in Zabbix?

[lepetal]

I have to compare two values changing in both directions (rising and falling) within an hour (items amount, for example). What formula may I use to calculate if the amount drops or rises on more than 20%? Does Zabbix calculated value support if conditions to support positive and negative change or it's possible to bypass it?

I'm trying to write something like this:

{api20prod:mysql.get_active_offers.count(0)}/{api20prod:mysql.get_active_offers.count(,,,1h)}*1 00 > 20

but what if mysql.get_active_offers.count(0) more than mysql.get_active_offers.count(,,,1h) ?

[lepetal]

No, it's not quite what I want. I want the following:

abs(current_amount - amount_1hour_ago)/current_amount * 100 > 20%

in terms of trigger.