Question

Name  | CountWin | CountFail | Failure% |
---------------------------------
TypeA |   100    |   50      |    50    |
TypeB |   100    |   5       |     5    |
TypeC |   100    |   100     |   100    |
TypeD |   100    |    0      |     0    |

我正在尝试用sql创建上面的表。结果不是我所期望的。结果如下

 Name  | CountWin | CountFail | Failure% |
---------------------------------
TypeA |   100    |   50      |     0    |
TypeB |   100    |   5       |     0    |
TypeC |   100    |   100     |     0    |
TypeD |   100    |    0      |     0    |

sql代码：

INSERT INTO #my_temp_table
  select type, date, CountWin, CountFail from myTable

select type, SUM(CountWin) as CountWin, SUM(CountFail) as CountFail, (((SUM(CountFail) / SUM(CountWin)) * 100) as Failure%
FROM #my_temp_table
WHERE date > DATEADD(day, -7, getdate())
GROUP BY type, date

只是想知道为什么我的（（（SUM（CountFail）/ SUM（CountWin））* 100没有返回正确的值

Answer 1

您的数据库可能正在执行整数除法。只需将计算结果如下：

select type, date, SUM(CountWin) as CountWin, SUM(CountFail) as CountFail,
      SUM(CountFail) * 100.0 / NULLIF(SUM(CountWin), 0) as Failure_percent
FROM #my_temp_table
WHERE date > DATEADD(day, -7, getdate())
GROUP BY type, date;

注意：

您的where子句正在使用getdate()上的时间。您更有可能：date > dateadd(day, -7, cast(getdate() as date))。
NULLIF()阻止除以0。
你的计算是一个比例，而不是百分比。也许你打算：SUM(CountFail) * 100.0 / NULLIF(SUM(CountWin + CountFail))

Answer 2

你必须将它投射到浮动

    INSERT INTO #my_temp_table
    select type, date, CountWin, CountFail from myTable

    select type, SUM(CountWin) as CountWin, SUM(CountFail) as 
    CountFail, (((SUM(CountFail) / CAST(SUM(CountWin) as float)) * 100) as 
    Failure%
    FROM #my_temp_table
    WHERE date > DATEADD(day, -7, getdate())
    GROUP BY type, date

SQL分割两个SUM（）函数

2 个答案: