創建包含上百萬行的表格的視圖

Question

我有一個包含18000000行（TABLE_A）的表格。我必須每15分鐘執行一次存儲過程，以從TABLE_A中選擇數據，進行一些計算並將結果插入到另一個表（TABLE_B）中。 TABLE_A的這個值來自包含不同設備讀數的文件。因此，桌子會越來越大。

這是文件內容的示例：

'2015-10-01 11:00:00.000';'par01';1 
'2015-10-01 12:00:00.000';'par02';1 
'2015-10-01 12:00:00.000';'par03';1 

我認爲這是更好地插入來自文件到另一個表（TABLE_C）的新值，並用該值進行計算TABLE_C。我想要一個查詢，當某個變量達到一個月的數據時，將大於一個月的行插入TABLE_A（對於我來說，一個月就足以進行計算）。因此，在TABLE_C中只有一個月的數據，計算的執行速度將比使用18000000行的速度更快。

這是表中的一個簡單的例子：

DECLARE @TABLE_C(timestamp datetime, parameter char(5), value int) 
DECLARE @TABLE_A(timestamp datetime, parameter char(5), value int) 

INSERT @TABLE_C values 
('2015-10-01 11:00:00.000','par01',1), 
('2015-10-01 12:00:00.000','par01',1), 
('2015-09-01 11:03:00.000','par01',2), 
('2015-09-01 12:03:00.000','par01',2), 
('2015-08-01 11:06:00.000','par01',3), 
('2015-08-01 12:06:00.000','par01',3), 

('2015-09-01 11:00:00.000','par02',1), 
('2015-09-01 12:00:00.000','par02',1), 
('2015-08-01 11:03:00.000','par02',2), 
('2015-08-01 12:03:00.000','par02',2), 
('2015-07-01 11:06:00.000','par02',3), 
('2015-07-01 12:06:00.000','par02',3), 

('2015-10-01 11:00:00.000','par03',1), 
('2015-10-01 12:00:00.000','par03',1), 
('2015-09-01 11:03:00.000','par03',2), 
('2015-09-01 12:03:00.000','par03',2), 
('2015-08-01 11:06:00.000','par03',3), 
('2015-08-01 12:06:00.000','par03',3) 

結果必須是財產以後像它：

INSERT @TABLE_C values 
('2015-10-01 11:00:00.000','par01',1), 
('2015-10-01 12:00:00.000','par01',1), 


('2015-09-01 11:00:00.000','par02',1), 
('2015-09-01 12:00:00.000','par02',1), 


('2015-10-01 11:00:00.000','par03',1), 
('2015-10-01 12:00:00.000','par03',1) 

INSERT @TABLE_A values 
('2015-09-01 11:03:00.000','par01',2), 
('2015-09-01 12:03:00.000','par01',2), 
('2015-08-01 11:06:00.000','par01',3), 
('2015-08-01 12:06:00.000','par01',3), 


('2015-08-01 11:03:00.000','par02',2), 
('2015-08-01 12:03:00.000','par02',2), 
('2015-07-01 11:06:00.000','par02',3), 
('2015-07-01 12:06:00.000','par02',3), 

('2015-09-01 11:03:00.000','par03',2), 
('2015-09-01 12:03:00.000','par03',2), 
('2015-08-01 11:06:00.000','par03',3), 
('2015-08-01 12:06:00.000','par03',3) 

Answer 1

編輯：這是一個新的解決方案。在開始時，它將計算每個參數及其開始和結束的最後一個月的邊界。如果這很快，將主要取決於「參數」中不同值的計數。

而且：你需要索引！

SET LANGUAGE english; 

DECLARE @t table(timestamp datetime, parameter char(5), value int) 

INSERT @t values 
('2015-10-01 11:00:00.000','par01',1), 
('2015-10-01 12:00:00.000','par01',1), 
('2015-09-01 11:03:00.000','par01',2), 
('2015-09-01 12:03:00.000','par01',2), 
('2015-08-01 11:06:00.000','par01',3), 
('2015-08-01 12:06:00.000','par01',3), 

('2015-09-01 11:00:00.000','par02',1), 
('2015-09-01 12:00:00.000','par02',1), 
('2015-09-01 11:03:00.000','par02',2), 
('2015-09-01 12:03:00.000','par02',2), 
('2015-08-01 11:06:00.000','par02',3), 
('2015-08-01 12:06:00.000','par02',3), 

('2015-10-01 11:00:00.000','par03',1), 
('2015-10-01 12:00:00.000','par03',1), 
('2015-09-01 11:03:00.000','par03',2), 
('2015-09-01 12:03:00.000','par03',2), 
('2015-08-01 11:06:00.000','par03',3), 
('2015-08-01 12:06:00.000','par03',3); 

WITH MaxDates AS 
(
    SELECT MAX(x.timestamp) AS maxDate,x.parameter 
    FROM @t AS x 
    GROUP BY x.parameter 
) 
,MonthFirst AS 
(
    SELECT * 
      ,CONVERT(DATETIME, CAST(YEAR(maxDate) AS VARCHAR(4)) + CAST(REPLACE(STR(MONTH(maxDate),2),' ','0') AS VARCHAR(2)) + '01', 104) AS StartOfMonth 
    FROM MaxDates 
) 
,MonthBorders AS 
(
    SELECT * 
      ,DATEADD(SECOND,-1,DATEADD(MONTH,1,StartOfMonth)) AS EndOfMonth 
    FROM MonthFirst 
) 
SELECT * 
FROM @t AS t 
INNER JOIN MonthBorders AS mb ON t.parameter=mb.parameter AND t.timestamp BETWEEN mb.StartOfMonth AND mb.EndOfMonth 
ORDER BY t.parameter; 

一個增強可能是（保存一個DATEADD）：

WITH MaxDates AS 
(
    SELECT MAX(x.timestamp) AS maxDate,x.parameter 
    FROM @t AS x 
    GROUP BY x.parameter 
) 
,MonthFirst AS 
(
    SELECT * 
      ,CONVERT(DATETIME, CAST(YEAR(maxDate) AS VARCHAR(4)) + CAST(REPLACE(STR(MONTH(maxDate),2),' ','0') AS VARCHAR(2)) + '01', 104) AS StartOfMonth 
    FROM MaxDates 
) 
,MonthBorders AS 
(
    SELECT * 
      ,DATEADD(MONTH,1,StartOfMonth) AS EndOfMonth 
    FROM MonthFirst 
) 
SELECT * 
FROM @t AS t 
INNER JOIN MonthBorders AS mb ON t.parameter=mb.parameter AND t.timestamp >= mb.StartOfMonth AND t.timestamp < mb.EndOfMonth 
ORDER BY t.parameter;