使用MySQL查询至少选修了“张立”同学选修的所有课程的学生学号和姓名
时间: 2023-11-16 19:44:35 浏览: 42
假设学生表为students,课程表为courses,选课表为selections,可以使用以下SQL语句查询至少选修了“张立”同学选修的所有课程的学生学号和姓名:
```
SELECT s.id, s.name
FROM students s
INNER JOIN selections sel ON s.id = sel.student_id
INNER JOIN courses c ON sel.course_id = c.id
WHERE c.name IN (
SELECT c2.name
FROM courses c2
INNER JOIN selections sel2 ON c2.id = sel2.course_id
INNER JOIN students s2 ON sel2.student_id = s2.id
WHERE s2.name = '张立'
)
GROUP BY s.id, s.name
HAVING COUNT(DISTINCT c.id) >= (
SELECT COUNT(DISTINCT c3.id)
FROM courses c3
INNER JOIN selections sel3 ON c3.id = sel3.course_id
INNER JOIN students s3 ON sel3.student_id = s3.id
WHERE s3.name = '张立'
);
```
该查询语句的思路是,首先在子查询中查询出“张立”选修的所有课程,然后在主查询中找到选修了这些课程的学生,并且确保这些学生选修的课程数量等于“张立”选修的课程数量。其中使用了INNER JOIN进行表的连接,GROUP BY进行分组,HAVING进行条件筛选。