What does <> mean in Ruby?

Question

I have this piece of code I programmed months ago:

@shipments = Shipment.joins(:invoice).where(:customer_id => @customer.id).where("customer_open_balance <> 0").order("file_number ASC")

I forgot what <> means. I searched online and looked through my Pickaxe book and can't find the answer.

Answer 1

<>是SQL ，表示“不等于”，又名!=