Question

我有以下代码

SELECT 
    Country,  
    COUNT(*) AS Records, 
    COUNT(SpecialField) AS Cnt, 
    COUNT(SpecialField)/COUNT(*) AS Perc_Hit 
FROM 
    Table
GROUP BY 
    Country
ORDER BY 
    Cnt DESC, Records DESC

此查询为Perc_Hit列返回0，即使它不应该。例如，一个中国有1000个'记录'和853'计数'，所以我期待.853作为我的结果。

有人可以告诉我为什么会出现这个错误吗？

提前致谢。

Answer 1

正如@ JohnCappelletti的评论所指出的，你正在进行整数除法。你可以像这样简单地将.0添加到任何一方：

select 
    Country
  , count(*) as Records
  , count(SpecialField) as Cnt
  , count(SpecialField)/(count(*)+.0) as Perc_Hit 
from Table
group by Country
order by Cnt desc, Records desc

Answer 2

你应该改变：

COUNT(SpecialField)/COUNT(*) AS Perc_Hit

到此：

CAST(COUNT(SpecialField) as float)/CAST(COUNT(*) as float) AS Perc_Hit

SQL Server：为什么COUNT（*）/ COUNT（Countries）As Hit给我0？

2 个答案: