Add null in array of params to SetFilter method
setFilter($field, array(1,2,null)) => the result is: AND .field IN (1,2) OR .field IS NULL setFilter($field, array(null)) => the result is: AND .field IS NULL All previous type of queries are persisted
setFilter($field, array(1,2,null)) => the result is: AND .field IN (1,2) OR .field IS NULL setFilter($field, array(null)) => the result is: AND .field IS NULL All previous type of queries are persisted