使用帶有搜索的CASE表達式的SELECT語句

Question

我創建了一個表scores，如下所示。

student_id course score 
1 math 90 
1 cs 70 
2 math 60 
2 cs 50 

我想通過規模來分類一個學生的所有得分：

>60 pass 
<60 fail 
=60 bottomline 

於是，我寫了一個select語句用CASE表達式作爲

select student_id, course, score = 
(case score  
    when score > 60 
    then 'pass' 
    when score < 60 
    then 'fail' 
    else 'bottomline' 
end) as 'result' 
from scores 
order by student_id 

然而結果集看起來像下面，並且result列未顯示類別爲pass, fail或bottomline根據規模。相反，所有result值都是0。

student_id course result 
1 math 0 
1 cs 0 
2 math 0 
2 cs 0 

哪裏是我錯引起的一切result值0 select語句？我正在使用MySQL數據庫服務器。

Answer 1

select student_id, course, score, 
    case      --<-- you dont need to mention column name here 
    when score < 60 then 'fail' 
    when score = 60 then 'bottomline' 
    when score > 60 then 'pass' 
    end as 'result' 
from scores 
order by student_id 

Sql Fiddle

Answer 2

爲什麼score = ...？

剛：

select student_id, course, score, 
(case score  
    when score > 60 
    then 'pass' 
    when score < 60 
    then 'fail' 
    else 'bottomline' 
end) as 'result' 
from scores 
order by student_id 

Answer 3

嘗試這樣

SLELECT student_id, course,Score 
    CASE 
    when score < 60 then 'fail' 
    when score > 60 then 'pass' 
    Else 'bottomline' 
    END 'result' 
FROM scores 
ORDER BY student_id 

Answer 4

Try This 
Create table scores (student_id int,course VARCHAR(100),score int); 
Insert into scores values(1,'math',90); 
Insert into scores values(1,'cs',70); 
Insert into scores values(2,'math',60); 
Insert into scores values(2,'cs',50); 

Select student_id, course,score, 
(case  
    when score > 60 
    then 'pass' 
    when score < 60 
    then 'fail' 
    else 'bottomline' 
end) as 'result' 
from scores 
order by student_id;