![](https://lstatic.shangxueba.com/jiandati/h5/images/m_q_title.png)
查询平均成绩良好,也就是≥80分的考生人数,查询语句就可以写成()。
A、WITH avgach (eeid,avgachieve) AS (SELECT eeid,AVG(achieve) FROM eeexam GROUP BY eeid ) SELECT COUNT(*) FROM avgach WHERE avgachieve>=80;
B、WITH avgach (eeid,avgachieve) (SELECT eeid,AVG(achieve) FROM eeexam GROUP BY eeid ) SELECT COUNT(*) FROM avgach WHERE avgachieve>=80;
C、SELECT COUNT(*) FROM (SELECT eeid,avg(achieve) FROM eeexam GROUP BY eeid )AS avgach (eeid,avgachieve) WHERE avgachieve>=80;
D、SELECT COUNT(*) FROM (SELECT eeid,avg(achieve) FROM eeexam GROUP BY eeid ) avgach (eeid,avgachieve) WHERE avgachieve>=80;
E、SELECT dname, (SELECT COUNT(*) FROM examiner WHERE department.dname = examiner.erdepa) FROM department WHERE avgachieve>=80;
F、SELECT * FROM erexam NATURAL LEFT OUTER JOIN exampaper;