Error trying to compare a GV with an inde field from another FC in Workflow

I'm trying to get the supplier code ( from a FC that is not asigned to this Workflow ) using the following method (see attched file). 
I get nothing out of that, it doesn't return anything, like it's not comparing the GV and the index field. I've double-checked and the GV and the index field have the same value. 

Thanks in advance

Hi Miguel,

The field DW_NOMBRE is probably a text field. Therefore, its value should be enclosed in single quotation marks, like this:
DW_NOMBRE = 'GV_Empresa'

Viele Grüße / With best regards,
Gerardo Lisanti

Thanks! That worked. 

But there's something else I want to ask you if you don't mind.

Instead of using "=" it would fit better using "like", sometimes the name isn't equal to the data in our database,  I've seen that you have to use "&" and "%". I've tried but I don't get anything but an error.