使用CTE将SQL插入 [英] SQL insert into using CTE
问题描述
由于sql中的插入语句,我遇到了性能问题。我正在使用CTE从多个表中选择数据并插入其他表中。到昨天为止,一切都很好。 Select花费不到一分钟的时间来检索数据,并永久插入其中。有人可以帮我了解我在做什么错。非常感谢您的帮助。谢谢。
I am facing a performance issue due to "Insert into" statement in sql. I am using a CTE to select data from multiple tables and insert into other table. It was working just fine until yesterday. Select takes less than a minute to retrieve the data where as insert into taking forever. Can some one please help me in understanding what i am doing wrong. Any help is highly appreciated. Thanks.
这是我的代码:
我在SP中使用此查询。我正在尝试将220万条记录加载到150万条记录表中。
I am using this query in an SP. I am trying to load 220K records to 1.5M records table.
;with CTE_A
AS
(
SELECT A1, A2,...
FROM dbo.A with (nolock)
WHERE A1 = <some condition>
GROUP BY a.A1,a.A2 , a.A3
), CTE_C as
(
SELECT C1, C2,....
FROM dbo.B with (nolock)
WHERE a.C1 = <some condition>
GROUP BY a.c1,a.C2 , a.C3
)
INSERT INTO [dbo].MainTable
SELECT
A1, A2, A3 , C1, C2, C3
FROM
CTE_A ta with (nolock)
LEFT OUTER JOIN
CTE_C tc with (nolock) ON ta.a1 = tc.a1 and ta.b1 = tc.b1 and ta.c1 = tc.c1
LEFT OUTER JOIN
othertable bs with (nolock) ON usd_bs.c = s.c
AND (A1 BETWEEN bs.a1 AND bs.a1)
AND bs.c1 = 1
推荐答案
尝试此方法(用临时表代替cte),性能必须比您的任务高得多
try this method (temp table instead cte), perfomance must be much higher for your task
IF OBJECT_ID('Tempdb..#CTE_A') IS NOT NULL
DROP TABLE #CTE_A
IF OBJECT_ID('Tempdb..#CTE_C') IS NOT NULL
DROP TABLE #CTE_C
-------------------------------------------------------------
SELECT A1 ,
A2 ,...
INTO #CTE_A --data set into temp table
FROM dbo.A WITH ( NOLOCK )
WHERE A1 = <some condition>
GROUP BY a.A1 ,
a.A2 ,
a.A3
-------------------------------------------------------------
SELECT C1 ,
C2 ,....
FROM dbo.B WITH ( NOLOCK )
INTO #CTE_C --data set into temp table
WHERE a.C1 = <some condition>
GROUP BY a.c1 ,
a.C2 ,
a.C3
INSERT INTO [dbo].MainTable
SELECT A1 ,
A2 ,
A3 ,
C1 ,
C2 ,
C3
FROM #CTE_A AS ta
LEFT JOIN #CTE_C AS tc ON ta.a1 = tc.a1
AND ta.b1 = tc.b1
AND ta.c1 = tc.c1
LEFT JOIN othertable AS bs ON usd_bs.c = s.c
AND ( A1 BETWEEN bs.a1 AND bs.a1 )
AND bs.c1 = 1
这篇关于使用CTE将SQL插入的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!