(1)通过全称量词变换实现方式查询至少选修了学号为“090120206”的学生所选修全部 课程的学生学号和姓名。
时间: 2024-06-13 10:07:09 浏览: 10
以下是通过全称量词变换实现方式查询至少选修了学号为“090120206”的学生所选修全部课程的学生学号和姓名的步骤:
1. 查询出学号为"090120206"的学生所选修的全部课程:
```sql
SELECT cno FROM sc WHERE sno = '090120206'
```
2. 查询出至少拥有这些课程的学生的学号:
```sql
SELECT sno FROM sc WHERE cno IN (SELECT cno FROM sc WHERE sno = '090120206') GROUP BY sno HAVING COUNT(DISTINCT cno) = (SELECT COUNT(DISTINCT cno) FROM sc WHERE sno = '090120206')
```
3. 根据学号查出学生姓名:
```sql
SELECT sno, sname FROM student WHERE sno IN (SELECT sno FROM sc WHERE cno IN (SELECT cno FROM sc WHERE sno = '090120206') GROUP BY sno HAVING COUNT(DISTINCT cno) = (SELECT COUNT(DISTINCT cno) FROM sc WHERE sno = '090120206'))
```
相关问题
编程实现存在量词和全称量词真值的计算
可以使用谓词逻辑来实现存在量词和全称量词的真值计算。其中,存在量词的真值计算可以通过找到满足该谓词的对象来实现,而全称量词的真值计算则需要对所有对象进行枚举并判断是否都满足该谓词。具体实现时,可以使用归纳证明、反证法等方法进行推理和证明。
查询供应了全部物资的公司编号。 请分别用 全称量词转exists的嵌套查询 和 带group+having中嵌套子查询的方式 完成此查询!!! 在答案中分别注明两类查询!
全称量词转exists的嵌套查询:
SELECT DISTINCT s.company_id
FROM supplies s
WHERE NOT EXISTS (
SELECT *
FROM materials m
WHERE NOT EXISTS (
SELECT *
FROM supplies s2
WHERE s2.material_id = m.material_id AND s2.company_id = s.company_id
)
);
带group having中嵌套子查询的方式:
SELECT s.company_id
FROM supplies s
GROUP BY s.company_id
HAVING COUNT(DISTINCT s.material_id) = (
SELECT COUNT(*)
FROM materials
);