Oracle 查询，苦思不解，求大神指教? 400 报错

Oracle 查询，苦思不解，求大神指教? 400 报错

1. 创建“学院班级学分达标情况统计表1”test7_03，依据pub.student， pub.course，pub.student_course统计形成表中各项数据，成绩>=60为及格计入学分，总学分>=10为达标，院系为空值的数据不统计在下表中，表结构：院系名称dname、班级class、学分达标人数p_count1、学分未达标人数p_count2、总人数p_count。以下为错误代码

   create table temp as select pub.student.sid,sum(credit) sum_credit from pub.student,pub.student_course,pub.course where pub.student.sid=pub.student_course.sid and pub.student_course.cid=pub.course.cid and dname is not null and score>=60 group by pub.student.sid create table a as select dname,class,count(u.sid) as p_count1  from (select sid,sum_credit from temp where sum_credit >=10) u,pub.student where pub.student.sid=u.sid group by dname,class create table b as select dname,class,count(temp.sid) as p_count from temp ,pub.student where temp.sid=pub.student.sid group by dname,class create table test7_03 as select a.dname,a.class,p_count1,p_count-p_count1 as p_count2 ,p_count from a,b where a.dname=b.dname and a.class=b.class