SQL 使用 CTE 插入
SQL insert into using CTE
由于 sql 中的 "Insert into" 语句,我遇到了性能问题。我正在使用 CTE 将来自多个 table 的 select 数据插入到其他 table 中。直到昨天它工作得很好。 Select 只需不到一分钟的时间就可以检索到永远插入的数据。有人可以帮助我理解我做错了什么吗?非常感谢任何帮助。谢谢
这是我的代码:
我在 SP 中使用这个查询。我正在尝试将 220K 条记录加载到 1.5M 条记录 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
试试这个方法(temp table 而不是 cte),性能必须比你的任务高得多
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
由于 sql 中的 "Insert into" 语句,我遇到了性能问题。我正在使用 CTE 将来自多个 table 的 select 数据插入到其他 table 中。直到昨天它工作得很好。 Select 只需不到一分钟的时间就可以检索到永远插入的数据。有人可以帮助我理解我做错了什么吗?非常感谢任何帮助。谢谢
这是我的代码:
我在 SP 中使用这个查询。我正在尝试将 220K 条记录加载到 1.5M 条记录 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
试试这个方法(temp table 而不是 cte),性能必须比你的任务高得多
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