我有多个可以临时重置的单调计数器。这些计数器在绘制图表时表现出锯齿行为(但它们并不是严格递增的)。我想要一份显示每个计数器每日最大值总和的月度报告。
到目前为止,我的策略是在计数器小于计数器前一个采样(也小于或等于下一个)的行上放置“1”。然后计算该列的运行总计,以识别没有重置的系列。
然后,我对每日间隔进行分组,计算当天每个系列的最大最小值,然后将这些部分相加以获得当天的总计。
我所拥有的可以工作,但运行需要大约 10 秒。执行计划显示了两大类:一种在 cteData 中,我认为另一种在 cteSeries 中。我觉得我应该能够消除其中一个,但我不知道如何做到这一点。
这段代码的结果是(我现在可以看到实际上是跳过了间隔边界的样本):
interval tagname total 2020-01-01 alpha 3 2020-01-01 bravo 4 2020-01-02 alpha 3 2020-01-02 bravo 4
IF OBJECT_ID('tempdb..#counter_data') IS NOT NULL
DROP TABLE #counter_data;
CREATE TABLE #counter_data(
t_stamp DATETIME NOT NULL
,tagname VARCHAR(32) NOT NULL
,val REAL NULL
PRIMARY KEY(t_stamp, tagname)
);
INSERT INTO #counter_data(t_stamp, tagname, val)
VALUES
('2020-01-01 04:00', 'alpha', 0)
,('2020-01-01 04:00', 'bravo', 0)
,('2020-01-01 08:00', 'alpha', 1)
,('2020-01-01 08:00', 'bravo', 1)
,('2020-01-01 12:00', 'alpha', 2)
,('2020-01-01 12:00', 'bravo', 2)
,('2020-01-01 16:00', 'alpha', 0)
,('2020-01-01 16:00', 'bravo', 3)
,('2020-01-01 20:00', 'alpha', 1)
,('2020-01-01 20:00', 'bravo', 4)
,('2020-01-02 04:00', 'alpha', 2)
,('2020-01-02 04:00', 'bravo', 5)
,('2020-01-02 08:00', 'alpha', 3)
,('2020-01-02 08:00', 'bravo', 6)
,('2020-01-02 12:00', 'alpha', 0)
,('2020-01-02 12:00', 'bravo', 7)
,('2020-01-02 16:00', 'alpha', 1)
,('2020-01-02 16:00', 'bravo', 8)
,('2020-01-02 20:00', 'alpha', 2)
,('2020-01-02 20:00', 'bravo', 9)
;
DECLARE @dateStart AS DATETIME = '2020-01-01';
DECLARE @dateEnd AS DATETIME = DATEADD(month, 2, @dateStart);
WITH cteData AS(
SELECT
t_stamp
,tagname
,val
,CASE
WHEN val < LAG(val) OVER(PARTITION BY tagname ORDER BY t_stamp)
AND val <= LEAD(val) OVER(PARTITION BY tagname ORDER BY t_stamp)
THEN 1
ELSE 0
END AS rn
FROM #counter_data
WHERE
t_stamp >= @dateStart AND t_stamp < @dateEnd
AND tagname IN(
'alpha'
,'bravo'
)
)
,cteSeries AS(
SELECT
CAST(t_stamp AS DATE) AS interval
,tagname
,val
,SUM(rn) OVER(PARTITION BY tagname ORDER BY t_stamp) AS series
FROM cteData
)
,cteSubtotal AS(
SELECT
interval
,tagname
,MAX(val) - MIN(val) AS subtotal
FROM cteSeries
GROUP BY interval, tagname, series
)
,cteGrandTotal AS(
SELECT
interval
,tagname
,SUM(subtotal) AS total
FROM cteSubtotal
GROUP BY interval, tagname
)
SELECT *
FROM cteGrandTotal
ORDER BY interval, tagname
最佳答案
我只需通过与前一行进行比较来计算每行中计数器的增加:
with cte
as
(
SELECT *,isnull(lag(val) over (partition by tagname order by t_stamp),0) as previousVal
FROM counter_data
)
SELECT cast(t_stamp as date),tagname, sum(case when val>previousVal then val-previousval else val end )
FROM cte
GROUP BY cast(t_stamp as date),tagname;
关于sql - 锯齿图案局部最大值的每日总计,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/63095318/