能用学生、课程、成绩三个表完成上面的题目吗
时间: 2023-07-24 15:18:03 浏览: 45
当然可以,下面是使用学生、课程、成绩三个表完成上述题目的SQL语句示例:
(1) 随机生成一个1至10之间的浮点数:
```sql
SELECT RAND()*9 + 1;
```
(2) 创建并调用一个标量函数求N!:
创建函数:
```sql
CREATE FUNCTION factorial(n INT)
RETURNS INT
BEGIN
DECLARE result INT DEFAULT 1;
WHILE n > 0 DO
SET result = result * n;
SET n = n - 1;
END WHILE;
RETURN result;
END;
```
调用函数:
```sql
SELECT factorial(5);
```
(3) 创建并调用一个内嵌表值函数:
创建函数:
```sql
CREATE FUNCTION get_student_by_course(course_name VARCHAR(50))
RETURNS TABLE (
student_id INT,
student_name VARCHAR(50),
score DECIMAL(10, 2)
)
BEGIN
RETURN SELECT s.student_id, s.student_name, c.score
FROM student s
JOIN score c
ON s.student_id = c.student_id
JOIN course t
ON c.course_id = t.course_id
WHERE t.course_name = course_name;
END;
```
调用函数:
```sql
SELECT * FROM get_student_by_course('Math');
```
(4) 创建并调用一个多语句表值函数:
创建函数:
```sql
CREATE FUNCTION get_student_by_score_range(min_score DECIMAL(10, 2), max_score DECIMAL(10, 2)))
RETURNS @result TABLE (
student_id INT,
student_name VARCHAR(50),
score DECIMAL(10, 2)
)
BEGIN
INSERT INTO @result
SELECT s.student_id, s.student_name, c.score
FROM student s
JOIN score c
ON s.student_id = c.student_id
JOIN course t
ON c.course_id = t.course_id
WHERE c.score BETWEEN min_score AND max_score;
RETURN;
END;
```
调用函数:
```sql
SELECT * FROM get_student_by_score_range(60, 90);
```
(5) 删除一个用户自定义函数:
```sql
DROP FUNCTION get_student_by_course;
```