CREATE TABLE table_19422702_1 (us_airdate VARCHAR, no_in_season VARCHAR)

How many U.S. air dates were from an episode in Season 4?
SELECT COUNT(us_airdate) FROM table_19422702_1 WHERE no_in_season = 4
SELECT COUNT("us_airdate") FROM "table_19422702_1" WHERE "no_in_season" = 4