Hello Everybody, Has anyone had success creating a facet that filters

You can either use a custom function named - executequery() and can run the SQL statement with "IS NULL" clause in your facet expression editor that will bring the appropriate records (column with which NULL needs to be compared) - the output of this will be a JSON Array and you can use custom function to parse JSON into array and this will solve your problem, OR as jasonr suggested, you can insert a Dummy String in the particular column when the value of that column is NULL, during inserting/updating the tuple in the database, and can then create a query rule with one of the input equal to that "Dummy String" inserted.

You can either use a custom function named - executequery() and can run the SQL statement with "IS NULL" clause in your facet expression editor that will bring the appropriate records (column with which NULL needs to be compared) - the output of this will be a JSON Array and you can use custom function to parse JSON into array and this will solve your problem, OR as jasonr suggested, you can insert a Dummy String in the particular column when the value of that column is NULL, during inserting/updating the tuple in the database, and can then create a query rule with one of the input equal to that "Dummy String" inserted.