Table: tv_episodes_23
Columns: episode
season
title
directed_by
written_by
original_airdate
production_code

Question: What is the highest episode number written by Harry Winkler?
SQL: SELECT MAX("episode") FROM tv_episodes_23 WHERE "written_by" = 'Harry Winkler'

Question: List all directors when Brad Radnitz was the writer?
SQL: SELECT "directed_by" FROM tv_episodes_23 WHERE "written_by" = 'Brad Radnitz'