SQL语句 - MS-SQL Server / 基础类

将学生选课成绩从百分制改为等级制（即A、B、C、D、E五级）。
使用存储过程

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SQL code:
select case
when score >=0 and score<20 then 'E'
when score >=20 and score<40 then 'D'
when score >=40 and score<60 then 'C'
when score >=60 and score<80 then 'B'
else 'A'

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select case
when (score-20)/20=0 then 'e'
when (score-20)/20=1 then 'd'
when (score-20)/20=2 then 'c'
when (score-20)/20=3 then 'b'
when (score-20)/20=4 then 'a' end

from tb

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SQL code:
select
case
when score score>80 then 'A'
when score score<60 then 'B'
when score score<40 then 'C'
when score score<20 then 'D'
else 'E'
end
from tb

---

SQL code:
select
case
when score score>=80 then 'A'
when score score>=60 then 'B'
when score score>=40 then 'C'
when score score>=20 then 'D'
else 'E'
end
from tb
楼上手误，修正

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SQL code: