题目内容（请给出正确答案）

[主观题]

SELECT DISTINCT erid FROM erexam WHERE erid IN （SELECT erid FROM examiner WHERE erdepa=’I

SELECT DISTINCT erid FROM erexam WHERE erid IN (SELECT erid FROM examiner WHERE erdepa=’IST’); 还有语句： SELECT DISTINCT erid FROM erexam,examiner WHERE examiner.erid=erexam.erid AND erdepa=’IST’; 这两个语句的执行结果不等价。

暂无答案

如搜索结果不匹配，请联系老师获取答案

您可能会需要：

重置密码查看订单联系客服

安装上学吧APP，拍照搜题省时又省心！

更多“SELECT DISTINCT erid FROM erex…”相关的问题

第1题

有语句： SELECT DISTINCT erid FROM erexam WHERE erid IN ( SELECT erid FROM examiner WHERE erdepa='IST'); 与其执行结果等价的关系代数表达式是（）。

A、

B、

C、

D、

E、

F、

G、

H、

I、

J、

K、

点击查看答案

第2题

有语句： SELECT DISTINCT erid FROM erexam WHERE erid IN ( SELECT erid FROM examiner WHERE erdepa='IST'); 与其执行结果等价的关系代数表达式是（）。

A、

B、

C、

D、

E、

F、

G、

H、

I、

J、

K、

点击查看答案

第3题

有语句： SELECT DISTINCT erid FROM erexam WHERE erid IN ( SELECT erid FROM examiner WHERE erdepa='IST'); 还有语句： SELECT DISTINCT erid FROM erexam,examiner WHERE examiner.erid=erexam.erid AND erdepa='IST'; 这

点击查看答案

第4题

SELECT erdepa,avg(ersalary) FROM examiner GROUP BY erdepa HAVING erdepa IN (select erdepa from examiner where ername='关晓彤')；该语句的功能是查询（）。

点击查看答案

第5题

检索全部考生都报考的试卷号和试卷名，查询语句就可以写成（）。

A、SELECT eid,ename FROM exampaper WHERE eid in (SELECT eid FROM eeexam GROUP BY eid HAVING COUNT(eeid)=(SELECT COUNT(eeid) FROM examinee) );

B、SELECT eid,ename FROM exampaper WHERE NOT EXIST (SELECT * FROM examinee WHERE NOT EXIST (SELECT * FROM eeexam WHERE examinee.eeid=eeid and exampaper.eid=eid) );

C、SELECT eid，ename FROM exampaper WHERE NOT EXISTS （（SELECT eeid FROM examinee） EXCEPT （SELECT eeid FROM eeexam WHERE exampaper.eid=eid））;

D、SELECT * FROM examinee ORDER BY eeid limit 2 offset ((SELECT count(*) FROM examinee)-2);

E、SELECT * FROM examinee ORDER BY eeid LIMIT (SELECT COUNT(*) FROM eeexam);

F、SELECT * FROM department WHERE EXISTS (SELECT * FROM examiner WHERE erdepa=department. dname AND eid= ername= '范冰冰');

G、SELECT eedepa, AVG(eeage) FROM examinee GROUP BY eedepa HAVING eedepa IN (SELECT eedepa FROM examinee WHERE eename='刘诗诗');

H、SELECT dname, (SELECT COUNT(*) FROM examiner WHERE department.dname = examiner.erdepa) FROM department;

I、SELECT (SELECT eedepa FROM examinee WHERE eeexam.eeid=examinee.eeid), AVG(achieve) FROM eeexam GROUP BY (SELECT eedepa FROM examinee WHERE eeexam.eeid=examinee.eeid);

点击查看答案

第6题

pgSQL语句： SELECT COUNT(DISTINCT erdepa) FROM examiner; 其查询的是( )。

A、考官的总人数

B、每一部门的考官人数

C、考官服务的院系数

D、每一考官服务的院系数

点击查看答案

第7题

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;