IF EXISTS 在 SQL 中设置变量

Question

如何在设置变量时使用if exists 子句？

我已经设置好了，所以顶部选择语句的结果（@F1Runs, @F2Runs, @F3Runs，全部用于对应的Date）插入到临时表#WeekEnding，然后从那里插入到实际表中。

问题在于，对于某些日期，部分或全部熔炉没有“运行次数”结果。因此，当我设置变量@F1Runs、@F2Runs 和@F3Runs 时，我试图找到一种方法来放置一个 IF EXISTS 语句或类似的东西，以便当它们不存在时它们作为 0 插入到表中。

我得到的错误是：

无法将值 NULL 插入列“F2Runs”、表“WWALMDB.dbo.WeeklyRuns”；列不允许空值。插入失败。

我的代码：

Select 
    jr.FurnaceID, Count(Distinct jr.JobID) As 'Number of Runs'
Into 
    #WeekEnding
From 
    dbo.JobReports jr
Where 
    jr.StartDateTime >= @StartDate 
    and jr.EndDateTime < @Enddate
Group By  
    jr.FurnaceID
Order By 
    Count(jr.JobID) DESC

Select @F1Runs = [Number of Runs]
From #WeekEnding
Where FurnaceID = 1

Select @F2Runs = [Number of Runs] 
From #WeekEnding
Where FurnaceID = 2

Select @F3Runs = [Number of Runs] 
From #WeekEnding
Where FurnaceID = 3

If Exists (Select wr.WeekEnding
           From WWALMDB.dbo.WeeklyRuns wr
           Where wr.WeekEnding = DATEADD(day, -1, @Enddate))
Begin
    Update WWALMDB.dbo.WeeklyRuns 
    Set F1Runs = @F1Runs,
        F2Runs = @F2Runs, 
        F3Runs = @F3Runs
    Where WeeklyRuns.WeekEnding = DATEADD(day, -1, @Enddate)
End
Else
Begin
    Insert Into WWALMDB.dbo.WeeklyRuns (WeekEnding, F1Runs, F2Runs, F3Runs)
    Values (DATEADD(day, -1, @Enddate), @F1Runs, @F2Runs, @F3Runs)
End

Answer 1

我的理解是 IF Exists 需要一个块，所以我不相信这会对你有所帮助。

我认为 ISNULL 是你的朋友

Select jr.FurnaceID, Count(Distinct jr.JobID) As 'Number of Runs'
Into #WeekEnding
From dbo.JobReports jr
Where jr.StartDateTime >= @StartDate and jr.EndDateTime < @Enddate
Group By jr.FurnaceID
Order By Count(jr.JobID) DESC

SET @F1Runs = ISNULL(Select [Number of Runs]
From #WeekEnding
Where FurnaceID = 1,0)

SET @F2Runs = (Select [Number of Runs] 
From #WeekEnding
Where FurnaceID = 2,0)

SET @F3Runs  = (Select [Number of Runs] 
From #WeekEnding
Where FurnaceID = 3,0)

If Exists ( Select wr.WeekEnding
            From WWALMDB.dbo.WeeklyRuns wr
            Where wr.WeekEnding = DATEADD(day, -1, @Enddate))
Begin
    Update WWALMDB.dbo.WeeklyRuns 
    Set F1Runs = @F1Runs,
        F2Runs = @F2Runs, 
        F3Runs = @F3Runs
    Where WeeklyRuns.WeekEnding = DATEADD(day, -1, @Enddate)
    End
    Else
Begin
    Insert Into WWALMDB.dbo.WeeklyRuns (WeekEnding, F1Runs, F2Runs, F3Runs)
    Values (DATEADD(day, -1, @Enddate), @F1Runs, @F2Runs, @F3Runs)
End

或

Select jr.FurnaceID, Count(Distinct jr.JobID) As 'Number of Runs'
Into #WeekEnding
From dbo.JobReports jr
Where jr.StartDateTime >= @StartDate and jr.EndDateTime < @Enddate
Group By jr.FurnaceID
Order By Count(jr.JobID) DESC

Select @F1Runs = [Number of Runs]
From #WeekEnding
Where FurnaceID = 1

Select @F2Runs =[Number of Runs] 
From #WeekEnding
Where FurnaceID = 2

Select @F3Runs = [Number of Runs] 
From #WeekEnding
Where FurnaceID = 3

If Exists ( Select wr.WeekEnding
            From WWALMDB.dbo.WeeklyRuns wr
            Where wr.WeekEnding = DATEADD(day, -1, @Enddate))
Begin
    Update WWALMDB.dbo.WeeklyRuns 
    Set F1Runs = ISNULL(@F1Runs,0),
        F2Runs = ISNULL(@F2Runs,0), 
        F3Runs = ISNULL(@F3Runs,0)
    Where WeeklyRuns.WeekEnding = DATEADD(day, -1, @Enddate)
    End
    Else
Begin
    Insert Into WWALMDB.dbo.WeeklyRuns (WeekEnding, F1Runs, F2Runs, F3Runs)
    Values (DATEADD(day, -1, @Enddate), @F1Runs, @F2Runs, @F3Runs)
End