-- Database schema
| Author : Id [ INTEGER ] primary_key , Name [ TEXT ] , Affiliation [ TEXT ] | Conference : Id [ INTEGER ] primary_key , ShortName [ TEXT ] , FullName [ TEXT ] , HomePage [ TEXT ] | Journal : Id [ INTEGER ] primary_key , ShortName [ TEXT ] , FullName [ TEXT ] , HomePage [ TEXT ] | Paper : Id [ INTEGER ] primary_key , Title [ TEXT ] , Year [ INTEGER ] , ConferenceId [ INTEGER ] Paper.ConferenceId = Conference.Id , JournalId [ INTEGER ] Paper.JournalId = Journal.Id , Keyword [ TEXT ] | PaperAuthor : PaperId [ INTEGER ] PaperAuthor.PaperId = Paper.Id , AuthorId [ INTEGER ] PaperAuthor.AuthorId = Author.Id , Name [ TEXT ] , Affiliation [ TEXT ] |
-- -- 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"?

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;