这段文字的意思update student set grade = ( select grade from (
来源:学生作业帮 编辑:百度作业网作业帮 分类:综合作业 时间:2024/06/17 01:33:40
这段文字的意思
update student
set grade = (
select grade from
(
select id,
case when score> 90 then 'a'
when score > 80 then 'b'
when score > 70 then 'c'
else 'd' end grade
from student
) a
where a.id = student.id
);
update student
set grade = (
select grade from
(
select id,
case when score> 90 then 'a'
when score > 80 then 'b'
when score > 70 then 'c'
else 'd' end grade
from student
) a
where a.id = student.id
);
![这段文字的意思update student set grade = ( select grade from (](/uploads/image/z/8420312-56-2.jpg?t=%E8%BF%99%E6%AE%B5%E6%96%87%E5%AD%97%E7%9A%84%E6%84%8F%E6%80%9Dupdate+student%E3%80%80%E3%80%80set+grade+%3D+%28%E3%80%80%E3%80%80select+grade+from%E3%80%80%E3%80%80%28)
只说这段代码希望达到的结果吧:根据student表里的各学生的score(分数)值设定grade字段的值(90分以上的为'a',80分以上的为'b',70分以上的'c',其他为'd')
不过感觉case那部分好像不太对,比如90分以上的会满足所有三个条件,那可能grade值应该会是'c'.
不过感觉case那部分好像不太对,比如90分以上的会满足所有三个条件,那可能grade值应该会是'c'.
这段文字的意思update student set grade = ( select grade from (
select sname,avg(grade) from sc,student wherestudent.sno=sc.
select Student.Sno,Sname,Ssex,Cname,Grade from Student,SC,Co
select s.name,s.course,s.grade from student as s inner join
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