1.编写一个表值函数返回所有以下要求的数据 输入一个学号,使用游标遍历成绩表数据,完成以下操作: 把该学生姓名、选修课程的门数,有哪些选课课程名,实得总学分(某门课及格才能得到学分,否则该课学分为0),输出结果使用一个字符串返回。
时间: 2024-03-11 08:47:47 浏览: 19
好的,我明白了。以下是一个基于SQL Server的表值函数,可以实现您的要求:
```
CREATE FUNCTION dbo.GetStudentCourseInfo (@StudentID INT)
RETURNS @Result TABLE (
Name VARCHAR(50),
CourseCount INT,
CourseNames VARCHAR(MAX),
TotalCredit DECIMAL(5,2)
)
AS
BEGIN
DECLARE
@Name VARCHAR(50),
@CourseCount INT,
@CourseNames VARCHAR(MAX),
@TotalCredit DECIMAL(5,2),
@CourseID INT,
@CourseName VARCHAR(50),
@CourseCredit DECIMAL(5,2),
@Grade CHAR(2);
-- 获取学生姓名
SELECT @Name = Name FROM Students WHERE StudentID = @StudentID;
-- 获取选修课程数、课程名、实得总学分
SET @CourseCount = 0;
SET @CourseNames = '';
SET @TotalCredit = 0;
DECLARE CourseCursor CURSOR FOR
SELECT CourseID, CourseName, Credit, Grade FROM Grades WHERE StudentID = @StudentID;
OPEN CourseCursor;
FETCH NEXT FROM CourseCursor INTO @CourseID, @CourseName, @CourseCredit, @Grade;
WHILE @@FETCH_STATUS = 0
BEGIN
IF @Grade IS NOT NULL AND CAST(@Grade AS INT) >= 60
BEGIN
SET @CourseCount += 1;
SET @CourseNames += @CourseName + ', ';
SET @TotalCredit += @CourseCredit;
END
FETCH NEXT FROM CourseCursor INTO @CourseID, @CourseName, @CourseCredit, @Grade;
END
CLOSE CourseCursor;
DEALLOCATE CourseCursor;
-- 去掉课程名字符串末尾的逗号和空格
SET @CourseNames = SUBSTRING(@CourseNames, 1, LEN(@CourseNames) - 2);
-- 将结果插入到表值函数返回的表中
INSERT INTO @Result (Name, CourseCount, CourseNames, TotalCredit)
VALUES (@Name, @CourseCount, @CourseNames, @TotalCredit);
RETURN;
END
```
您可以将该函数保存到数据库中,并使用以下语句调用它:
```
SELECT * FROM dbo.GetStudentCourseInfo(1);
```
其中,1是您要查询的学生的ID。函数将会返回一个包含所需信息的表格。