From year 1991 to 2000, calculate the difference betweeen the total number of papers published under the conference "International Conference on Supercomputing " and "Informatik & Schule"?
From year 1991 to 2000 refers to Year BETWEEN 1991 AND 2000; papers refers to Paper.Id; 'International Conference on Supercomputing' AND 'Informatik & Schule' are the FullName of conference; calculate the difference between the total number of papers of these two conferences refers to SUBTRACT(SUM(Paper.Id where FullName = 'International Conference on Supercomputing'), SUM(Paper.Id where FullName = 'Informatik & Schule'))
SELECT SUM(CASE WHEN T2.FullName = 'Informatik & Schule' THEN 1 ELSE 0 END) - SUM(CASE WHEN T2.FullName = 'International Conference on Supercomputing' THEN 1 ELSE 0 END) AS DIFF FROM Paper AS T1 INNER JOIN Conference AS T2 ON T1.ConferenceId = T2.Id WHERE T1.Year > 1990 AND T1.Year < 2001