[讨论]SQL视图中为何无法执行CASE语句??

yealone

在网上下了《一道褒贬不一的 SQL 考试题》,见下语句,试着操作,为何无法执行,还请帮助!!!

SELECT 课程ID,MAX(课程名称) AS 课程名称,AVG(成绩) AS 平均成绩,100 * SUM(CASE WHEN 成绩 >=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分数
 FROM T
 GROUP BY 课程ID
 ORDER BY 及格百分数 DESC

zhengjialon

在ACCESS中用?那要用IFF函数代替的.

meeting

如果在sqlserver中用,这样试试

SELECT 课程ID,MAX(课程名称) AS 课程名称,AVG(成绩) AS 平均成绩,100 * SUM(CASE WHEN 成绩 >=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分数
 FROM T
 GROUP BY 课程ID
 ORDER BY 100*SUM(CASE WHEN 成绩 >=60 THEN 1 ELSE 0 END)/COUNT(*)  DESC

yealone

谢谢!