select SUM(case when total < 60 then 1 else 0 end) as ‘studentMarks1‘, sum(case when total > 80 then 1 else 0 end) as ‘studentMarks2‘ from School where Id = ‘8‘
参考：https://stackoverflow.com/questions/42481826/how-to-use-multiple-where-clause-in-one-sql-query
原文：https://www.cnblogs.com/zealousness/p/12671690.html