ORA-00979: 不是 Oracle 中的 GROUP BY 表达式

Question

我无法在 Oracle 上执行此代码，错误显示：

"ORA-00979: not a GROUP BY expression"

但是，我能够运行它在 MySQL 上成功。
这是怎么发生的？

SELECT CONCAT(i.lname, i.fname) AS inst_name, 
           CONCAT(s.lname, s.fname) AS stu_name, 
           t.avg_grade AS stu_avg_grade
    FROM(
    SELECT instructor_id, student_id, AVG(grade) as avg_grade, RANK() OVER(PARTITION BY instructor_id ORDER BY grade DESC) AS rk
    FROM grade
    GROUP BY 1,2) t
    JOIN instructor i 
    ON t.instructor_id = i.instructor_id
    JOIN student s 
    ON s.student_id = t.student_id
    WHERE t.rk = 1
    ORDER BY 3 DESC

Answer 1

您不能在 Oracle 中使用像 GROUP BY 1,2 这样的序数。此外，RANK() 函数中的 ORDER BY grade 子句有问题。请记住，分析函数在之后计算 GROUP BY 聚合，因此 grade 不再可用。这是一个应该可以正常工作的版本：

SELECT CONCAT(i.lname, i.fname) AS inst_name, CONCAT(s.lname, s.fname) AS stu_name, t.avg_grade AS stu_avg_grade FROM ( SELECT instructor_id, student_id, AVG(grade) AS avg_grade, RANK() OVER (PARTITION BY instructor_id ORDER BY AVG(grade) DESC) AS rk FROM grade GROUP BY instructor_id, student_id ) t INNER JOIN instructor i ON t.instructor_id = i.instructor_id INNER JOIN student s ON s.student_id = t.student_id WHERE t.rk = 1 ORDER BY t.avg_grade DESC;

ORA-00979: 不是 Oracle 中的 GROUP BY 表达式

ORA-00979: not a GROUP BY expression in Oracle

oracle

group-by