Sql 使用存储过程传入字符串时，如何输出光标？

嘿，伙计们，我正在处理一个存储过程，但我一直在研究如何输出下面的光标。我想让它接受我给它的任何课程，并吐出计数、课程编号和课程描述。以下是我目前掌握的情况：

EXEC STUDENT_COUNT_COURSE('CS 101');

召唤

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您需要一个游标变量来保存resultset，可以将其作为过程输出参数输出，但通过函数返回它是处理问题的常用方法。像这样：

CREATE OR REPLACE FUNCTION STUDENT_COUNT_COURSE 
    (p_CrsNum IN COURSE.COURSENUM%TYPE)
    RETURN sys_refcursor
IS
    rc sys_refcursor;
BEGIN
    open rc for 
          SELECT     CourseDesc.courseNum
                     , CourseDesc.courseDesc
                     , COUNT(DISTINCT Student.studentID)
          FROM         Course INNER JOIN
                      CourseDesc ON Course.courseNum = CourseDesc.courseNum INNER JOIN
                      Grades ON Course.courseID = Grades.courseID INNER JOIN
                      Student ON Grades.studentID = Student.studentID
          WHERE     (CourseDesc.courseNum = p_CrsNum)
          GROUP BY CourseDesc.courseNum, CourseDesc.courseDesc;

    return rc;
end; 

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我认为您可能需要这样的内容（只需读取光标并将其发送到标准输出）

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但是首先你必须创建光标（APC发布的方式）

我觉得很愚蠢。。。我的dbms_output.put_行缺少一个下划线，并且在select语句的末尾有一个额外的逗号

以下是我使用的解决方案：

CREATE OR REPLACE PROCEDURE STUDENT_COUNT_COURSE(p_CrsNum IN COURSE.COURSENUM%TYPE)
AS
  cursor cursor1 is SELECT CourseDesc.courseNum, 
                    CourseDesc.courseDesc, 
                    COUNT(DISTINCT Student.studentID) as "Count"
          FROM      Course INNER JOIN
                    CourseDesc ON Course.courseNum = CourseDesc.courseNum INNER JOIN
                    Grades ON Course.courseID = Grades.courseID INNER JOIN
                    Student ON Grades.studentID = Student.studentID
          WHERE     (CourseDesc.courseNum = p_CrsNum)
          GROUP BY CourseDesc.courseNum, CourseDesc.courseDesc;
BEGIN          
    FOR c IN cursor1
    LOOP
        IF C."Count"=1 THEN
           DBMS_OUTPUT.PUT_LINE('There is '||c."Count"||' student in ' || c.courseNum ||', '||c.CourseDesc);
        ELSE
            DBMS_OUTPUT.PUT_LINE('There are '||c."Count"||' students in ' || c.courseNum ||', '||c.CourseDesc);
        END IF;
    END LOOP;
END;

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嘿，我需要一个存储过程。我已经更新了一点代码。不过，这让我大吃一惊。

LOOP 
 FETCH cursor1
  INTO  couse_num, course_name, num_students;
EXIT WHEN v_cursor%NOTFOUND;
 DBMS_OUTPUT.PUT_LINE(couse_num|| ' , ' || course_name|| ' , ' || num_students);
END LOOP;
CLOSE cursor1;

CREATE OR REPLACE PROCEDURE STUDENT_COUNT_COURSE(p_CrsNum IN COURSE.COURSENUM%TYPE)
AS
  cursor cursor1 is SELECT CourseDesc.courseNum, 
                    CourseDesc.courseDesc, 
                    COUNT(DISTINCT Student.studentID) as "Count"
          FROM      Course INNER JOIN
                    CourseDesc ON Course.courseNum = CourseDesc.courseNum INNER JOIN
                    Grades ON Course.courseID = Grades.courseID INNER JOIN
                    Student ON Grades.studentID = Student.studentID
          WHERE     (CourseDesc.courseNum = p_CrsNum)
          GROUP BY CourseDesc.courseNum, CourseDesc.courseDesc;
BEGIN          
    FOR c IN cursor1
    LOOP
        IF C."Count"=1 THEN
           DBMS_OUTPUT.PUT_LINE('There is '||c."Count"||' student in ' || c.courseNum ||', '||c.CourseDesc);
        ELSE
            DBMS_OUTPUT.PUT_LINE('There are '||c."Count"||' students in ' || c.courseNum ||', '||c.CourseDesc);
        END IF;
    END LOOP;
END;