I am trying to set a filter on a table with 4 variables which work great if all 4 variables have information. How can I set this up if say only 2 out of the 4 have information. My code is currently:

SELECT planrep
SET FILTER TO INLIST(planrep.dept,&lcdept) AND INLIST(planrep.factory,&lcfactory) AND INLIST(planrep.country,&lccountry) AND INLIST(planrep.season,&lcseason)

There may be a time that I only want to filter by just lcseason.