如何使用多个 case 语句更新多个值 null

Question

这是我的桌子：

Site_name | date& Time              | PowerOutput         
----------+-------------------------+------------------
ACT0001   | 2013-07-21 01:00:00.000 | 196.852984494331   
ACT0001   | 2013-07-21 02:00:00.000 |   0   
xyz0001   | 2013-07-21 03:00:00.000 | 196.852984494331   
xyq0001   | 2013-07-21 04:00:00.000 | 196.958395639561 
xys0001   | 2013-07-21 05:00:00.000 |   0
xyd0001   | 2013-07-21 06:00:00.000 | 197.20098185022 
xye0001   | 2013-07-21 07:00:00.000 |   0 
xyg0001   | 2013-07-21 08:00:00.000 |   0     
cfg0001   | 2013-07-21 09:00:00.000 | 197.412144323522 
acb0001   | 2013-07-21 10:00:00.000 |   0 
bdf0001   | 2013-07-21 11:00:00.000 |   0 
olk0001   | 2013-07-21 12:00:00.000 | 196.886233049016 

我有这张表，我正在尝试更新“零”位置的值。 如果只有一个零，那么我可以更新表格，但如果有连续的零，我发现很难更新表格。

逻辑是：

• ((上一个值-下一个值)/上一个值)*100

  如果这是真的，那么它应该插入前一个值

• ((上一个值-下一个值)/上一个值)*100 >=5

  如果这是真的，那么它应该保持为零。

这是我目前的代码：

with cte as
(
    SELECT  
        *,
        lead(pr_output,1) OVER (ORDER BY (select null)) As PreviousValue,
        lag(pr_output,1) OVER (ORDER BY (select null)) As NextValue
    FROM
        [dbo].[Mytable]
)
,ctee as
(
    select 
        *,
        abs((PreviousValue*100-NextValue*100)/NextValue) as CheckFlag
    from
        cte 
)
select
    Site_name,[DATE&Time],
    case 
        when pr_output <>0 then pr_output
        else
            case 
                when CheckFlag >= 5 then 0
                else PreviousValue
            end
    end as pr_output
from 
    ctee

我得到的错误是

遇到除以零错误。

请告诉我我做错了什么。如果他们是这样做的另一种方式？

感谢任何帮助。

输出应该是：

Site_name | date& Time              | PowerOutput         
----------+-------------------------+------------------
ACT0001   | 2013-07-21 01:00:00.000 | 196.852984494331   
ACT0001   | 2013-07-21 02:00:00.000 | 196.852984494331   
xyz0001   | 2013-07-21 03:00:00.000 | 196.852984494331   
xyq0001   | 2013-07-21 04:00:00.000 | 196.958395639561 
xys0001   | 2013-07-21 05:00:00.000 | 196.958395639561
xyd0001   | 2013-07-21 06:00:00.000 | 197.20098185022 
xye0001   | 2013-07-21 07:00:00.000 |   0 
xyg0001   | 2013-07-21 08:00:00.000 |   0     
cfg0001   | 2013-07-21 09:00:00.000 | 197.412144323522 
acb0001   | 2013-07-21 10:00:00.000 |   0
bdf0001   | 2013-07-21 11:00:00.000 |   0 
olk0001   | 2013-07-21 12:00:00.000 | 196.886233049016 

Answer 1

在除以它之前需要检查 NextValue 是否为零..

希望这能解决您的问题。

with cte as
(
    SELECT  
        *,
        lead(pr_output,1) OVER (ORDER BY (select null)) As PreviousValue,
        lag(pr_output,1) OVER (ORDER BY (select null)) As NextValue
    FROM
        [dbo].[Mytable]
)
,ctee as
(
    select 
        *,
        abs((PreviousValue*100-NextValue*100)/(case when NextValue = 0 then 1 else NextValue end)) as CheckFlag
    from
        cte 
)
select
    Site_name,[DATE&Time],
    case 
        when pr_output <>0 then pr_output
        else
            case 
                when CheckFlag >= 5 then 0
                else PreviousValue
            end
    end as pr_output
from 
    ctee