Basic SQL query not working with Field Filter

Hi Guys

I got an specific problem in which I’m struggling a few days ago. The problem comes when I try to use a variable of my query as Field Filter. I linked it to a field (countryname) of my the table SITE, but when I add the filter in the dashboard and choose any option from that dropdown I got “no results” in the report.

I’m not sure if I’m doing something wrong in the configuration, my database (MySQL) can be not well estructured or I’m misunderstanding the concept of the Field Filters

This is the query:

select * FROM
[[WHERE COUNTRYNAME= {{variable_name}}]];

and this is the configuration of my variable:

My bad, the field filter already check the parameter,

I was doing and incorrect sintaxis:

where countryname=collections.countryname= 'colombia'

so the correct query should be:

select * FROM
[[WHERE {{variable_name}}]];