同班同名的人也可能存在的
delete from studentStore
where id not in(
select max(id) from studentStore group by class,student
)
delete from studentStore
where id not in(
select max(id) from studentStore group by class,student
)
解决方案 »
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where id not in(
select max(id) from studentStore group by class,student,subject,score
)这样?
DELETE FROM STUDENTSTORE
WHERE ID NOT IN(
SELECT MAX(ID) FROM STUDENTSTORE GROUP BY CLASS,STUDENT
)
3、SELECT student from studentScore WHERE score>80 GROUP BY student;
4、SELECT SUM(a.s) from ( (SELECT student,SUM(studentScore.score) as s FROM studentScore GROUP BY student) as a);
SELECT student,SUM(studentScore.score) as s FROM studentScore GROUP BY student;
delete from studentscore t1
where t1.rowid in (
select v1.rowid from (
select v1.rowid,
row_number() over(partition by v1.class, v1.student, v1.subject, v1.score order by v1.id) rn
from studentscore v1
) vv1
where vv1.rn > 1
);
第三个错了
select student
from studentscore t1
group by student
having count(1) = count(case when score > 80 then 1 else null end)
;
第四个明显考的分析函数
select t1.student,
sum(t1.score) over(partition by t1.student),
sum(t1.score) over(partition by t1.class)
from studentscore t1
where t1.class = 1
;
第一问,原题不严谨,没说按什么确定是哪个学生,不加class就不加吧。
第二问,limit没用过,不做评论