我想避免在表格上进行子选择来比较两个时期以及趋势是否向下。
此选择获取一个周期内的百分比
SELECT user, (SUM(value1)/SUM(value2)) AS percentage1
FROM table
WHERE (date BETWEEN @start1 AND @end1)
GROUP BY user
ORDER BY 2
这个查询得到了我想要的结果,但效率不是很高,因为有超过 1 亿行。
SELECT t1.user, (SUM(t1.value1)/SUM(t1.value2)) AS percentage1,
(SELECT (SUM(t2.value1)/SUM(t2.value2)) AS percentage2
FROM table AS t2
WHERE t2.userID = t1.userID
AND (t2.date BETWEEN @start2 AND @end2)
)
FROM table AS t1
WHERE (t1.date BETWEEN @start1 AND @end1)
AND (SUM(t1.value1)/SUM(t1.value2)) < (SELECT (SUM(t2.value1)/SUM(t2.value2))
FROM table AS t2
WHERE t2.userID = t1.userID
AND (t2.date BETWEEN @start2 AND @end2)
)
GROUP BY t1.user
有更好的方法吗?一种解决方案可能是只设置一个日期期间,然后按月(日期)、年(日期)进行分组,并与上个月进行比较,而不是使用两个确切的日期。但是按月份和年份分组只会为每个用户提供几行,而我想避免这种情况。
只是想要一个像这样干净的结果:
Adam, 43%, 47%
Lisa, 22%, 25%
John, 18%, 34%
排除这样的行,因为趋势百分比较低
Bill, 24%, 18%
Nina, 84%, 56%
SQL-Server 2016 Enterprise 是数据库。
最佳答案
你可以试试这个。
SELECT G1.user, G1.percentage1, G2.percentage2
FROM
( SELECT t1.user, t1.userID
(SUM(t1.value1)/SUM(t1.value2)) AS percentage1,
FROM table AS t1
WHERE
(t1.date BETWEEN @start1 AND @end1)
GROUP BY t1.user, t1.userID
) AS G1
INNER JOIN (
SELECT t2.userID, (SUM(t2.value1)/SUM(t2.value2)) AS percentage2
FROM table AS t2
WHERE
(t2.date BETWEEN @start2 AND @end2)
GROUP BY t2.userID
) AS G2 ON G1.userID = G2.userID
WHERE
G1.percentage1 < G2.percentage2
但是如果您只想使用表格中的一项选择,那么您也可以尝试此操作。
DECLARE @start DATE
DECLARE @end DATE
SET @start = CASE WHEN @start1 < @start2 THEN @start1 ELSE @start2 END
SET @end = CASE WHEN @end1 > @end2 THEN @end1 ELSE @end2 END
SELECT * FROM (
SELECT t.userID,
SUM( CASE WHEN t.date BETWEEN @start1 AND @end1 THEN t.value1 END ) / SUM( CASE WHEN t.date BETWEEN @start1 AND @end1 THEN t.value2 END ) AS percentage1,
SUM( CASE WHEN t.date BETWEEN @start2 AND @end2 THEN t.value1 END ) / SUM( CASE WHEN t.date BETWEEN @start2 AND @end2 THEN t.value2 END ) AS percentage2,
FROM table AS t
WHERE
(t.date BETWEEN @start AND @end)
GROUP BY t.userID
) AS SQ WHERE percentage1 < percentage2
关于sql - T-SQL : SELECT posts where trend is downwards on two time periods,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/50498617/