SELECT FlightNum, Origin FROM opensearch_dashboards_sample_data_flights WHERE NULL IS NULL
SELECT FlightNum, Origin FROM opensearch_dashboards_sample_data_flights WHERE NULL IS NOT NULL
SELECT FlightNum, Origin FROM opensearch_dashboards_sample_data_flights WHERE NULL IS NULL AND NULL IS NULL
SELECT FlightNum, Origin FROM opensearch_dashboards_sample_data_flights WHERE NULL IS NULL OR NULL IS NULL