From 1593 onwards, what is the difference between the number of comedy works and history works?
From 1593 onwards refers to Date > 1593; comedy works and history works refers to GenreType = 'comedy' and GenreType = 'History'
SELECT SUM(IIF(GenreType = 'Comedy', 1, 0)) - SUM(IIF(GenreType = 'History', 1, 0)) FROM works WHERE Date > 1593