[英]How to tune the following query?
這個查詢給了我想要的結果,但是我不能每次都運行這個查詢.2個循環使我付出了代價。 .so,是否有其他方法可以存儲此結果或更改查詢,從而使我的花費更少。
DECLARE @Temp TABLE (
[SiteID] VARCHAR(100)
,[StructureID] INT
,[row] DECIMAL(4, 2)
,[col] DECIMAL(4, 2)
)
DECLARE @siteID VARCHAR(100)
,@structureID INT
,@struct_row INT
,@struct_col INT
,@rows_count INT
,@cols_count INT
,@row INT
,@col INT
DECLARE structure_cursor CURSOR
FOR
SELECT StructureID
,SiteID
,Cols / 8.5 AS Cols
,Rows / 11 AS Rows
FROM Structure
WHERE SellerID = 658 --AND StructureID = 55
OPEN structure_cursor
FETCH NEXT
FROM structure_cursor
INTO @structureID
,@siteID
,@struct_col
,@struct_row
SELECT @rows_count = 1
,@cols_count = 1
,@row = 1
,@col = 1
WHILE @@FETCH_STATUS = 0
BEGIN
WHILE @row <= @struct_row
BEGIN
WHILE @col <= @struct_col
BEGIN
--PRINT 'MEssage';
INSERT INTO @Temp (
SiteID
,StructureID
,row
,col
)
VALUES (
@siteID
,@structureID
,@rows_count
,@cols_count
)
SET @cols_count = @cols_count + 1;
SET @col = @col + 1;
END
SET @cols_count = 1;
SET @col = 1;
SET @rows_count = @rows_count + 1;
SET @row = @row + 1;
END
SET @row = 1;
SET @col = 1;
SET @rows_count = 1;
FETCH NEXT
FROM structure_cursor
INTO @structureID
,@siteID
,@struct_col
,@struct_row
END
CLOSE structure_cursor;
DEALLOCATE structure_cursor;
SELECT * FROM @Temp
使用基於集合的操作執行此操作。 我認為您只想insert . . . select
insert . . . select
insert . . . select
:
INSERT INTO @Temp (SiteID, StructureID, row, col)
SELECT StructureID, SiteID, Cols / 8.5 AS Cols, Rows / 11 AS Rows
FROM Structure
WHERE SellerID = 658;
您應該避免使用游標,除非出於某種原因(例如調用存儲過程或在每行上使用動態SQL)確實需要游標時。
編輯:
閱讀邏輯,您似乎想根據每行中的限制插入行。 您仍然不想使用游標。 為此,您需要一個數字生成器,並且master..spt_values
是一個方便的數字生成器(如果具有足夠的行)。 所以:
with n as (
select row_number() over (order by (select null)) as n
from master..spt_values
)
INSERT INTO @Temp (SiteID, StructureID, row, col)
SELECT StructureID, SiteID, ncol.n / 8.5 AS Cols, nrow.n / 11 AS Rows
FROM Structure s JOIN
n ncol
ON ncol.n <= s.struct_col CROSS JOIN
n nrow
ON nrow <= s.struct_row
WHERE SellerID = 658;
您可以生成行數和列數,然后對它們進行交叉應用,如下所示。 我沒有列出您的SellerID條件。
;WITH Cols
AS
(
SELECT StructureID, SiteID, CAST(Cols / 8.5 AS INT) AS Col
FROM Structure
UNION ALL
SELECT s.StructureID, s.SiteID, Col - 1
FROM Structure s
INNER JOIN Cols c ON s.StructureID = c.StructureID AND s.SiteID = c.SiteID
WHERE Col > 1
)
, Rows
AS
(
SELECT StructureID, SiteID, CAST(Rows / 11 AS INT) AS Row
FROM Structure
UNION ALL
SELECT s.StructureID, s.SiteID, Row - 1
FROM Structure s
INNER JOIN Rows r ON s.StructureID = r.StructureID AND s.SiteID = r.SiteID
WHERE Row > 1
)
--INSERT INTO @Temp (SiteID, StructureID, row, col)
SELECT s.SiteID, s.StructureID, r.Row, c.Col
FROM Structure s
CROSS APPLY Cols c
CROSS APPLY Rows r
WHERE s.StructureID = c.StructureID AND s.SiteID = c.SiteID
AND s.StructureID = r.StructureID AND s.SiteID = r.SiteID
我們可以使用CROSS APPLY
和CTE
做到這一點。
CREATE TABLE Structure(SiteID varchar(20), StructureID int,
Cols decimal(18,2), [Rows] decimal(18,2))
INSERT INTO Structure (SiteID, StructureID, Cols, [Rows])
VALUES
('MN353970', 51,17,22),
('MN272252', 52,17,11)
;WITH RowCTE([Rows]) AS
(
SELECT 1
UNION ALL
SELECT 2
),
ColCTE(Cols) AS
(
SELECT 1
UNION ALL
SELECT 2
)
SELECT SiteID, StructureID, R.Rows, C.Cols
FROM Structure s
CROSS APPLY
(
SELECT Cols FROM ColCTE
) C
CROSS APPLY
(
SELECT [Rows] FROM RowCTE
) R
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