CREATE TABLE "table1_2342078_4" (
  "episode_num" real,
  "season_num" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_airdate" text,
  "production_code_num" real
);

Question: What is the highest episode number written by Harry Winkler?
SQL: SELECT MAX("episode_num") FROM "table1_2342078_4" WHERE "written_by"='Harry Winkler';

Question: List all directors when Brad Radnitz was the writer?
SQL: SELECT "directed_by" FROM "table1_2342078_4" WHERE "written_by"='Brad Radnitz';