假设我有一个带有数字列的表(让我们称之为“score”)。

我想生成一个计数表,显示分数在每个范围内出现的次数。

例如:

score range  | number of occurrences
-------------------------------------
   0-9       |        11
  10-19      |        14
  20-29      |         3
   ...       |       ...

在这个示例中,有11行分数在0到9之间,14行分数在10到19之间,3行分数在20到29之间。

有什么简单的方法吗?你有什么建议吗?


当前回答

我会用一种稍微不同的方式来做,这样它就不必定义每种情况:

select t.range as [score range], count(*) as [number of occurences]
from (
  select FLOOR(score/10) as range
  from scores) t
group by t.range

没有测试过,但你懂的…

其他回答

我会用一种稍微不同的方式来做,这样它就不必定义每种情况:

select t.range as [score range], count(*) as [number of occurences]
from (
  select FLOOR(score/10) as range
  from scores) t
group by t.range

没有测试过,但你懂的…

select t.blah as [score range], count(*) as [number of occurences]
from (
  select case 
    when score between  0 and  9 then ' 0-9 '
    when score between 10 and 19 then '10-19'
    when score between 20 and 29 then '20-29'
    ...
    else '90-99' end as blah
  from scores) t
group by t.blah

如果在MySQL中,请确保使用'range'以外的单词,否则在运行上述示例时会出现错误。

我在这里看到的答案在SQL Server的语法中行不通。我会用:

select t.range as [score range], count(*) as [number of occurences]
from (
  select case 
    when score between  0 and  9 then ' 0-9 '
    when score between 10 and 19 then '10-19'
    when score between 20 and 29 then '20-29'
    ...
    else '90-99' end as range
  from scores) t
group by t.range

编辑:见评论

我在这里是因为我有类似的问题,但我发现简短的答案是错误的,一个连续的“情况下”是太多的工作,看到任何重复在我的代码伤害我的眼睛。这就是解

SELECT --MIN(score), MAX(score),
    [score range] = CAST(ROUND(score-5,-1)AS VARCHAR) + ' - ' + CAST((ROUND(score-5,-1)+10)AS VARCHAR),
    [number of occurrences] = COUNT(*)
FROM order
GROUP BY  CAST(ROUND(score-5,-1)AS VARCHAR) + ' - ' + CAST((ROUND(score-5,-1)+10)AS VARCHAR)
ORDER BY MIN(score)


在我看来,James Curran的回答是最简洁的,但输出并不正确。对于SQL Server,最简单的语句如下:

SELECT 
    [score range] = CAST((Score/10)*10 AS VARCHAR) + ' - ' + CAST((Score/10)*10+9 AS VARCHAR), 
    [number of occurrences] = COUNT(*)
FROM #Scores
GROUP BY Score/10
ORDER BY Score/10

这假设了一个我用来测试它的#Scores临时表,我只是用0到99之间的随机数填充了100行。