使用WHILE 语句求1~100之和。 2.使用学籍管理数据库编写以下程序。 1)在Student 表中查找名字为“章会”的学生。如果存在，则显示该学生的信息；否则显示“查无此人”。 2)查询有无选修100200号课程的记录。如果有，则显示“有”，并查询选修100200号课程的人数。 3)查询20192602 班级的学生信息，要求列出的字段为：本班级学生的学号、姓名、性别、出生日期、住址。 4)使用学籍管理数据库,定义一个游标Student_Delete,删除 Student 表中的第一行数据。 5)使用学籍管理数据库，定义一个游标Student Display，将所有学生的姓名、家庭地址显示出来

1. 求1~100之和的程序：

DECLARE
    sum NUMBER := 0;
    i NUMBER := 1;
BEGIN
    WHILE i <= 100 LOOP
        sum := sum + i;
        i := i + 1;
    END LOOP;
    DBMS_OUTPUT.PUT_LINE('1~100之和为：'|| sum);
END;

2. 学籍管理数据库的程序：

-- 1)在Student表中查找名字为“章会”的学生
DECLARE
    v_id Student.s_id%TYPE;
    v_name Student.s_name%TYPE;
    v_gender Student.s_gender%TYPE;
    v_birthday Student.s_birthday%TYPE;
    v_address Student.s_address%TYPE;
BEGIN
    SELECT s_id, s_name, s_gender, s_birthday, s_address
    INTO v_id, v_name, v_gender, v_birthday, v_address
    FROM Student
    WHERE s_name = '章会';
    
    DBMS_OUTPUT.PUT_LINE('学号：' || v_id || '，姓名：' || v_name || '，性别：' || v_gender || '，出生日期：' || v_birthday || '，住址：' || v_address);
EXCEPTION
    WHEN NO_DATA_FOUND THEN
        DBMS_OUTPUT.PUT_LINE('查无此人');
END;

-- 2)查询有无选修100200号课程的记录
DECLARE
    v_count NUMBER;
BEGIN
    SELECT COUNT(*)
    INTO v_count
    FROM SC
    WHERE c_id = '100200';
    
    IF v_count > 0 THEN
        DBMS_OUTPUT.PUT_LINE('有');
        
        SELECT COUNT(*)
        INTO v_count
        FROM SC
        WHERE c_id = '100200';
        
        DBMS_OUTPUT.PUT_LINE('选修100200号课程的人数为：' || v_count);
    ELSE
        DBMS_OUTPUT.PUT_LINE('无');
    END IF;
END;

-- 3)查询20192602班级的学生信息
DECLARE
    CURSOR c_student IS
        SELECT s_id, s_name, s_gender, s_birthday, s_address
        FROM Student
        WHERE s_class = '20192602';
        
    v_id Student.s_id%TYPE;
    v_name Student.s_name%TYPE;
    v_gender Student.s_gender%TYPE;
    v_birthday Student.s_birthday%TYPE;
    v_address Student.s_address%TYPE;
BEGIN
    OPEN c_student;
    LOOP
        FETCH c_student INTO v_id, v_name, v_gender, v_birthday, v_address;
        EXIT WHEN c_student%NOTFOUND;
        DBMS_OUTPUT.PUT_LINE('学号：' || v_id || '，姓名：' || v_name || '，性别：' || v_gender || '，出生日期：' || v_birthday || '，住址：' || v_address);
    END LOOP;
    CLOSE c_student;
END;

-- 4)删除Student表中的第一行数据
DECLARE
    CURSOR c_student IS
        SELECT s_id
        FROM Student
        WHERE ROWNUM = 1;
        
    v_id Student.s_id%TYPE;
BEGIN
    OPEN c_student;
    FETCH c_student INTO v_id;
    CLOSE c_student;
    
    DELETE FROM Student
    WHERE s_id = v_id;
END;

-- 5)将所有学生的姓名、家庭地址显示出来
DECLARE
    CURSOR c_student IS
        SELECT s_name, s_home_address
        FROM Student;
        
    v_name Student.s_name%TYPE;
    v_address Student.s_home_address%TYPE;
BEGIN
    OPEN c_student;
    LOOP
        FETCH c_student INTO v_name, v_address;
        EXIT WHEN c_student%NOTFOUND;
        DBMS_OUTPUT.PUT_LINE('姓名：' || v_name || '，家庭地址：' || v_address);
    END LOOP;
    CLOSE c_student;
END;