我有一个 SQL 语句,它可以获取不同活动类型(家庭作业、测验等)的成绩,如果该类型的分数最低,它就会下降,否则,它仍然存在。错误如下以及 SQL 代码。
SELECT Student.firstName, Student.lastName, 'Grades' =
CASE
WHEN Grades.activityType = 'Homework' THEN
CASE WHEN Policy.drop_hw = 1 THEN
(AVG(SUM(Grades.grade) - MIN(Grades.grade))) * (Policy.homework / 100)
ELSE
(AVG(Grades.grade) * (Policy.homework / 100))
END
END, Course.courseNum, Course.sectNum, Grades.activityType
FROM ...
以下是我得到的错误:
- Cannot perform an aggregate function on an expression containing an aggregate or a subquery.
- Column 'Policy.drop_hw' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.