这是什么SQL语法啊,从未见过,

这是什么SQL语法啊,从未见过,以下是全文select sc.cid as 课程ID,course.name as 课程名,SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85],SUM(CASE WHEN score BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85-70],SUM(CASE WHEN score BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [60 - 70],SUM(CASE WHEN score< 60 THEN 1 ELSE 0 END) AS [