SQLZOO SELECT 来自诺贝尔#14

Question

物理化学整理完之后不知道名字怎么排序了！

问题：表达式主语 IN ('Chemistry','Physics') 可以是 用作值 - 它将是 0 或 1。

按主题和获奖者姓名排序显示 1984 年获奖者和主题； 但最后列出化学和物理。

SELECT winner, subject, subject IN('Physics', 'Chemistry')
FROM nobel
WHERE yr=1984
ORDER BY CASE
 WHEN subject IN ('Physics', 'Chemistry') = 0 THEN subject IN ('Physics', 'Chemistry')
 WHEN subject IN ('Physics', 'Chemistry') =  THEN winner
 ELSE winner 
End

问题的详细信息http://sqlzoo.net/wiki/SELECT_from_Nobel_Tutorial

Answer 1

我在 SQLZOO 中尝试过，下面的 SQL 给出了正确的结果。

SELECT winner, subject
FROM nobel
WHERE yr=1984
ORDER BY subject IN ('Physics','Chemistry'), subject, winner

Answer 2

正如 @AllenJohnson 指出的，这是由 SQL 引擎设置引起的。

SQLZOO使用其问题指南中的表达式，但没有指出SQL引擎会影响语法正确与否。

表达式 subject IN ('Chemistry','Physics') 可以用作一个值 - 它将是 0 或 1。

如果您选择 SQLZOO SQL 引擎作为 MySQL，您可以使用：

select 
    winner
    , subject
from nobel
where yr=1984
order by 
    subject in ('Physics','Chemistry')
    , subject
    , winner

如果您选择 SQLZOO SQL 引擎作为 Microsoft SQL，您可以使用：

select
    winner
    , subject
from nobel
where yr = 1984
order by
    case
        when subject in ('Physics', 'Chemistry') then 1
        else 0
    end
    , subject
    , winner

Answer 3

in

运算符不能像您一样在选择中使用，但您在

order by

子句中使用case表达式走在正确的道路上。你想要的是这样的：

SELECT 
  winner, subject
FROM 
  nobel
WHERE 
  yr = 1984
ORDER BY 
  CASE WHEN subject IN ('Physics','Chemistry') THEN 1 ELSE 0 END, 
  subject, 
  winner

正如问题所述，

IN ('Physics','Chemistry')

将计算为1或0，因此它可以用于某些数据库中的完整案例表达式；尽管它不符合标准 ANSI SQL。我相信 MySQL 会允许，但例如 MS SQL 不会。

Answer 4

select winner, subject
from nobel
where yr = '1984'
order by ( case subject
           when 'Chemistry' then 1
           when 'Physics'   then 2
           else 0
           end), subject, winner

Answer 5

SELECT 
        winner, 
        subject
 FROM 
        nobel
 WHERE 
        yr=1984
 ORDER BY 
        subject IN ('Physics','Chemistry'),
        subject,
        winner

Answer 6

## Heading ##SELECT *
From (Select Top (Select count(winner) from nobel where yr = 1984 AND subject NOT IN ('Chemistry', 'Physics')) winner, subject
    FROM nobel
    WHERE yr=1984 AND subject NOT IN ('Chemistry', 'Physics')
    Order By subject, winner) AS zero
UNION
Select *
From (Select TOP (Select count(winner) from nobel where yr = 1984 AND subject IN ('Chemistry', 'Physics')) winner, subject
    From nobel
    Where yr = 1984 AND subject IN ('Chemistry', 'Physics')
    Order By subject, winner) AS one

它显示结果但不是正确答案。