--都是挺简单的题目，想学好ORACLE的话，这些是必须的，有空自己多练习练习.没人能老帮你的.呵呵
--没有测试过，可能会有部分问题，呵呵

--1
CREATE OR REPLACE FUNCTION GET_LESSON_SCORE
(
       V_StuName IN student.studentName%TYPE,
       V_LessionName IN student.lessionName%TYPE,
       N_Score OUT student.score %TYPE
)
RETURN NUMBER
IS
BEGIN
       SELECT score INTO N_Score  FROM student 
       WHERE student.studentName = V_StuName
       AND student.lessionName = V_LessionName;
       RETURN N_Score;
END GET_LESSON_SCORE;


--2
SELECT student.studentName FROM STUDENT WHERE STUDENT.score = 
(SELECT MAX(SCORE) FROM STUDENT)

--3
SELECT * FROM STUDENT WHERE STUDENT.STUDENTID NOT IN
(SELECT STUDENT.STUDENTID FROM STUDENT WHERE SCORE >= 70)

------解决方案--------------------
ls 有点小错误
SQL code

SQL> select * from student;

STUD STUDENTNAME          LESSONNAME                SCORE
---- -------------------- -------------------- ----------
1    张三                 语文                         69
2    张三                 数学                         65
3    李四                 语文                         68
4    李四                 数学                         78
5    王五                 语文                         67

----------------------------------------1--------------------------
SQL> ed
已写入 file afiedt.buf

  1  CREATE OR REPLACE FUNCTION GET_LESSON_SCORE
  2  (
  3         V_StudentName IN student.studentName%TYPE,
  4         V_LessonName IN student.lessonName%TYPE,
  5         N_Score OUT student.score %TYPE
  6  )
  7  RETURN NUMBER
  8  IS
  9  BEGIN
 10         SELECT score INTO N_Score  FROM student
 11         WHERE student.studentName = V_StudentName
 12         AND student.lessonName = V_LessonName;
 13         RETURN N_Score;
 14* END;
SQL> /

函数已创建。

SQL> exec :score:=get_lesson_score('张三','语文',:score);

PL/SQL 过程已成功完成。

SQL> print score

     SCORE
----------
        69

----------------------------------------2--------------------------
SQL> ed
已写入 file afiedt.buf

  1  SELECT studentname FROM
  2  (SELECT studentname
  3  FROM student
  4  GROUP       BY studentname
  5  ORDER BY SUM(score) DESC
  6  )
  7* WHERE rownum<=1
SQL> /

STUDENTNAME
--------------------
李四
----------------------------------------3--------------------------
SQL> ed
已写入 file afiedt.buf

  1  SELECT DISTINCT studentname FROM student
  2  WHERE studentname NOT IN (
  3* select studentname from student where score>=70)
SQL> /

STUDENTNAME
--------------------
王五
张三

SQL>