SQL - 如果count result = 0，則運行第二個Query

Question

我的SELECT查詢都在下面工作，並返回兩個單獨結果的值。 我想要做的是，如果第一個SELECT語句返回0並且有時由於我們工作的性質，我希望第二個忽略第一個返回零的可能。 如果第一個返回大於零的結果，那么我不希望第二個運行。

我一直在尋找和嘗試不同的IF ELSE等，但由於使用的具體日期/時間公式，我認為這可能是不可能的，或者我可能必須完全重寫。 有一個目的，但我不會厭煩你。 提前致謝！

Declare @StartDate as DateTime
Declare @EndDate as DateTime
Declare @TodaysDate as DateTime
Declare @Previous as DateTime
Declare @Previous2 as DateTime

set @TodaysDate = GETDATE()
set @Previous = DATEADD(day,-1,@TodaysDate)
set @Previous2 = DATEADD(day,-2,@TodaysDate)

-- SELECT Statetment one starts here

set @StartDate = cast(convert(varchar(4), datepart(yyyy, getdate())) + '-' +
convert(varchar(2), datepart(mm, @Previous)) + '-' +
convert(varchar(2), datepart(dd, @Previous)) + ' ' +
'05:00' as datetime)
set @EndDate = cast(convert(varchar(4), datepart(yyyy, getdate())) + '-' +
convert(varchar(2), datepart(mm, @Previous)) + '-' +
convert(varchar(2), datepart(dd, @Previous)) + ' ' +
'16:59' as datetime)

SELECT Count(*) as FirstShfitPrevious
FROM [TOL_PROD_DB].[dbo].[tblLOT_CTRL_Active_Component] 
WHERE  Close_Time_Stamp between @StartDate and @EndDate

-- Query 2 Starts, Declarations already made at beginning

set @StartDate = cast(convert(varchar(4), datepart(yyyy, getdate())) + '-' +
convert(varchar(2), datepart(mm, @Previous2)) + '-' +
convert(varchar(2), datepart(dd, @Previous2)) + ' ' +
'05:00' as datetime)
set @EndDate = cast(convert(varchar(4), datepart(yyyy, getdate())) + '-' +
convert(varchar(2), datepart(mm, @Previous2)) + '-' +
convert(varchar(2), datepart(dd, @Previous2)) + ' ' +
'16:59' as datetime)

SELECT Count(*) as FirstShfitPrevious2
FROM [TOL_PROD_DB].[dbo].[tblLOT_CTRL_Active_Component] 
WHERE  Close_Time_Stamp between @StartDate and @EndDate

Answer 1

您可以嘗試將第一個查詢結果的值存儲在變量中，然后檢查值

declare @myVar int

SELECT @myVar = Count(*) as FirstShfitPrevious
FROM [TOL_PROD_DB].[dbo].[tblLOT_CTRL_Active_Component] 
WHERE  Close_Time_Stamp between @StartDate and @EndDate)

if(@myVar = 0)
//Here your second query logic
begin
set @StartDate = cast(convert(varchar(4), datepart(yyyy, getdate())) + '-' +
convert(varchar(2), datepart(mm, @Previous2)) + '-' +
convert(varchar(2), datepart(dd, @Previous2)) + ' ' +
'05:00' as datetime)
set @EndDate = cast(convert(varchar(4), datepart(yyyy, getdate())) + '-' +
convert(varchar(2), datepart(mm, @Previous2)) + '-' +
convert(varchar(2), datepart(dd, @Previous2)) + ' ' +
'16:59' as datetime)

SELECT Count(*) as FirstShfitPrevious2
FROM [TOL_PROD_DB].[dbo].[tblLOT_CTRL_Active_Component] 
WHERE  Close_Time_Stamp between @StartDate and @EndDate
end

Answer 2

使用NOT存在..

if NOT Exists
(Select 1  as FirstShfitPrevious--first query
FROM [TOL_PROD_DB].[dbo].[tblLOT_CTRL_Active_Component] 
WHERE  Close_Time_Stamp between @StartDate and @EndDate
)
Begin
SELECT Count(*) as FirstShfitPrevious2--second query
FROM [TOL_PROD_DB].[dbo].[tblLOT_CTRL_Active_Component] 
WHERE  Close_Time_Stamp between @StartDate and @EndDate
END
Else 
Begin
--First query
End

Answer 3

甚至那樣：

SELECT TOP 1 Count(*) as FirstShfitPrevious2
FROM [TOL_PROD_DB].[dbo].[tblLOT_CTRL_Active_Component] 
WHERE  Close_Time_Stamp between @StartDate and @EndDate
GROUP BY CAST(Close_Time_Stamp AS DATE)
ORDER BY CAST(Close_Time_Stamp AS DATE) DESC

期間涵蓋兩個日期范圍。