为什么这个查询不能正常工作?
SELECT e.*
FROM enrolled e
FULL OUTER JOIN student s ON e.studentid = s.sid
WHERE ((e.quarter = 'Fall') OR (e.quarter = 'Spring'))
GROUP BY e.studentid
HAVING count(e.studentid) == 1;
发生的错误:
ORA-00937: 不是单组组函数 00937. 00000 - “不是单组组函数” *原因:*操作:行错误:1 列:8
谢谢,