sql - 尝试选择另一个属性时出现错误 ORA-00937

Question

我正在尝试按专业预测学生的最高平均 GPA。

如果我不选择major并忽略它，它会起作用。

这就是我所拥有的：

SELECT  MAX(avg_gpa), major
FROM    (SELECT major, AVG(gpa) AS avg_gpa
        FROM Student
        GROUP BY  major);

我的错误：ORA-00937: not a single-group group function

Answer 1

SELECT  
  MAX(avg_gpa) as max_avg_gpa, 
  min(major) keep (dense_rank first order by avg_gpa desc) as best_major
FROM (
  SELECT 
    major, 
    AVG(gpa) AS avg_gpa
  FROM Student
  GROUP BY  major
)