SQL查询，以确定何时达到阈值

Question

我有一个有趣的SQL问题我会很感激一些建议。

我与列的表：

DateAdded 
Score 
Team 

用户将进入自己的得分但是他们不一定会为了（有些人可能会，如果他们不每天使用该系统进行回日期）。

将团队成绩的每个成员加在一起，达到阈值得分的团队首先获胜。

我想要一个查询，它会告诉我哪个团队首先达到了阈值以及在哪个日期。

Answer 1

我认为日发现的第一个记录，这是你想要的实现。

SELECT TOP 1 T1.Dateadded, T1.Team FROM Table1 T1 
JOIN Table1 T2 
    ON T1.Team = T2.Team 
    and T1.Dateadded >= T2.Dateadded 
GROUP BY T1.Dateadded, T1.Team 
HAVING SUM(T2.Score) >= @Threshold 
ORDER BY T1.Dateadded 

SQL Fiddle

Answer 2

您可以使用DENSE_RANK来确定达到阈值的最佳/第一队。

WITH CTE AS 
(
    SELECT 
    DateAdded, Score, Team, 
    DENSE_RANK() OVER (Order By DateAdded ASC, Score DESC) AS Rank 
    FROM dbo.TableName 
    WHERE 
    Score >= Threshold 
) 
SELECT 
    DateAdded, Score, Team 
FROM CTE 
WHERE 
    Rank = 1 

请注意，这可能会返回多个团队。

Answer 3

你需要的是累计和。而且，SQL Server 2008不支持它。好消息，SQL Server 2012确实如此。

所以，你可以用一个相关子查询做到这一点：

select team, min(dateadded) as FirstPastThreshold 
from (select dateadded, score, team, 
      (select sum(score) from t t2 where t2.team = t.team and t2.dateadded <= t.dateadded) as cumulativescore 
     from t 
    ) t 
where cumulativescore>= @threshhold 
group by team 

Answer 4

你可以添加一个第四列称为currentThresholdScore。当插入新记录时，当前阈值分数列将是该记录分数加上之前插入的所有记录的值。然后检查当前阈值分数是否超过发送邮件的阈值等。

Answer 5

您可以对此问题使用子查询。只需添加一列，它列出了当前得分加上过去成绩的总和查询，然后由超过阈值

Sql Fiddle

Use tempdb 
Create Table Scoring (DateAdded DateTime, Score INT, Team INT) 
INSERT Scoring SELECT GetDate(), 100, 1 
INSERT Scoring SELECT GetDate()+1, 150, 1 
INSERT Scoring SELECT GetDate()+1, 50, 2 
INSERT Scoring SELECT GetDate()+2, 75, 2 
INSERT Scoring SELECT GetDate()-10, 75, 2 


DECLARE @Threshhold INT 
SET @Threshhold = 125 

-- Table which includes a cumulative score 
;WITH tbl AS 
(
SELECT 
    Team, 
    DateAdded, 
    Score, 
    -- This column calculates the current score + the sum of past scores 
    IsNull((SELECT Sum(t2.Score) CumScore FROM Scoring t2 WHERE t2.Team = t.Team AND t2.DateAdded < t.DateAdded),0) 
    + Score AS CumScore 
FROM Scoring t 
) 

-- Find first record > threshold 
SELECT TOP 1 * FROM tbl 
WHERE CumScore >= @Threshhold 
ORDER BY DateAdded ASC