[英]SQL Insert Into Temp Table in both If and Else Blocks
我正在嘗試根據 SQL 2005 中的條件結果填充臨時表。無論哪種方式,臨時表都將具有相同的結構,但將根據條件使用不同的查詢進行填充。 下面的簡化示例腳本在ELSE
塊INSERT INTO
語法檢查中失敗,錯誤為:
數據庫中已經有一個名為“#MyTestTable”的對象。
DECLARE @Id int
SET @Id = 1
IF OBJECT_ID('tempdb..#MyTestTable') IS NOT NULL DROP TABLE #MyTestTable
IF (@Id = 2) BEGIN
SELECT 'ABC' AS Letters
INTO #MyTestTable;
END ELSE BEGIN
SELECT 'XYZ' AS Letters
INTO #MyTestTable;
END
我可以在IF/ELSE
語句之前創建臨時表,然后在條件塊中執行INSERT SELECT
語句,但該表將有很多列,我試圖提高效率。 這是唯一的選擇嗎? 或者有什么方法可以使這項工作?
謝謝,馬特
回答晚了 8 年,但我很驚訝沒有人想到:
select * into #MyTempTable from...
where 1=2
IF -- CONDITION HERE
insert into #MyTempTable select...
ELSE
insert into #MyTempTable select...
簡單,快速,而且有效。 不需要動態sql
您遇到的問題不是您正在填充臨時表,而是您正在嘗試創建該表。 SQL 解析您的腳本並發現您正試圖在兩個不同的地方創建它,因此引發錯誤。 意識到“執行路徑”不可能同時命中兩個 create 語句是不夠聰明的。 使用動態 SQL 將不起作用; 我試過
DECLARE @Command varchar(500)
DECLARE @Id int
SET @Id = 2
IF OBJECT_ID('tempdb..#MyTestTable') IS NOT NULL DROP TABLE #MyTestTable
IF (@Id = 2) BEGIN
SET @Command = 'SELECT ''ABC'' AS Letters INTO #MyTestTable'
END ELSE BEGIN
SET @Command = 'SELECT ''XYZ'' AS Letters INTO #MyTestTable'
END
EXECUTE (@Command)
select * from #MyTestTable
但臨時表的持續時間與動態會話一樣長。 所以,唉,看來您必須先聲明該表,然后再填充它。 編寫和支持的代碼可能很笨拙,但它的執行效率足夠高。
在您提供的場景中,您可以執行此操作
DECLARE @Id int
SET @Id = 1
IF OBJECT_ID('tempdb..#MyTestTable') IS NOT NULL DROP TABLE #MyTestTable
SELECT
CASE WHEN (@Id = 2)
THEN 'ABC'
ELSE 'XYZ'
END AS Letters
INTO #MyTestTable;
但否則您將需要在這樣的if statement
之前創建表
Create Table #MyTestTable (
MyValue varchar(3)
)
IF (@Id = 2) BEGIN
Insert Into (MyValue)
SELECT 'ABC' AS Letters;
END ELSE BEGIN
Insert Into (MyValue)
SELECT 'XYZ' AS Letters;
END
如果無法預先創建臨時表並且不想將核心邏輯放在動態 SQL 中,我會使用以下解決方案。
IF 1 = 1 -- Replace with actual condition
BEGIN
SELECT * INTO #tmp1 FROM dbo.Table1
END
ELSE
BEGIN
SELECT * INTO #tmp2 FROM dbo.Table2
END
-- Inserting data into global temp table so sql server can't complain on not recognizing in a context
DECLARE @Command VARCHAR(MAX)
IF OBJECT_ID('tempdb..#tmp1') IS NOT NULL
BEGIN
SET @Command = 'SELECT * INTO ##tmp FROM #tmp1'
END
ELSE
BEGIN
SET @Command = 'SELECT * INTO ##tmp FROM #tmp2'
END
EXECUTE(@Command)
SELECT * INTO #tmpFinal FROM ##tmp -- Again passing data back to local temp table from global temp table to avoid seeing red mark
IF OBJECT_ID('tempdb..##tmp') IS NOT NULL DROP TABLE ##tmp
IF OBJECT_ID('tempdb..#tmp1') IS NOT NULL DROP TABLE #tmp1
IF OBJECT_ID('tempdb..#tmp2') IS NOT NULL DROP TABLE #tmp2
SELECT * FROM #tmpFinal
IF OBJECT_ID('tempdb..#tmpFinal') IS NOT NULL DROP TABLE #tmpFinal
這是一個老問題,但對於來到這里的其他人:
用戶 Philip Kelley 給出的動態 SQL 答案不適用於本地臨時表 ( #Mytemp
)。 您可以做的是創建動態 SQL 以將其插入到全局臨時表 ( ##MyTemp
) 中,稍后可以刪除該表。
DECLARE @Command varchar(500)
DECLARE @Id int
SET @Id = 2
IF OBJECT_ID('tempdb..#MyTestTable') IS NOT NULL DROP TABLE ##MyTestTable
IF (@Id = 2) BEGIN
SET @Command = 'SELECT ''ABC'' AS Letters INTO ##MyTestTable'
END ELSE BEGIN
SET @Command = 'SELECT ''XYZ'' AS Letters INTO ##MyTestTable'
END
EXECUTE (@Command)
select * from ##MyTestTable
DROP ##MyTestTable
此代碼可以幫助您
--creating temptable using columns of two existing tables
--you can create your temp table Using other methods
select top 0 VI.*,VU.FullName
into #mytemptable
from dbo.Items VI inner join
dbo.Users as VU
on VU.Id=VI.Id
--insert your data base on your condition
if(i<2) --First Condition
begin
INSERT INTO #mytemptable
SELECT VI.*,VU.FullName
from dbo.Items VI inner join
dbo.Users as VU
on VU.Id=VI.Id
end
Else if(2<i) --Second Condition
begin
INSERT INTO #mytemptable
SELECT VI.*,VU.FullName
from dbo.Items VI inner join
dbo.Users as VU
on VU.Id=VI.Id
end
select * from #mytemptable --show result
drop table #mytemptable --drop table if its needed
此代碼適用於 sql server 2014 我不知道它是否適用於 sql 2005
我試過這個:
SELECT S1.* INTO #MytestTable
FROM
( SELECT 'ABC' AS Letters WHERE 1 = CASE @Id=2 THEN 1 ELSE 2 END
UNION
SELECT 'XYZ' AS Letters WHERE 1 = CASE @Id=1 THEN 1 ELSE 2 END
) AS S1
如果稍后您需要向#MyTestTable 添加列,此解決方案會更好,因為否則您必須在重新運行腳本之前物理刪除它,這在測試條件下很煩人。
你可以試試這個代碼。
IF (CONDITION HERE)
begin
select * into #MyTempTable from tablename ....
end
ELSE
truncate table #MyTempTable
insert into #MyTempTable
select * from tablename ....
end
謝謝!!!
在這兩種情況下,您都可以在 SELECTing INTO 之前刪除該表。例如:
DECLARE @Id int
SET @Id = 1
IF (@Id = 2) BEGIN
IF OBJECT_ID('tempdb..#MyTestTable') IS NOT NULL DROP TABLE #MyTestTable
SELECT 'ABC' AS Letters
INTO #MyTestTable;
END ELSE BEGIN
IF OBJECT_ID('tempdb..#MyTestTable') IS NOT NULL DROP TABLE #MyTestTable
SELECT 'XYZ' AS Letters
INTO #MyTestTable;
END
評論后更新:
這很煩人。
兩個單獨的臨時表怎么樣? 然后在 If/Else 登錄后,檢查每個是否存在,如果存在,則選擇進入第三個臨時表? 這可能表現不佳,但這是否重要取決於您需要它做什么。
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