Question

我在Access数据库中运行SQL查询以累积每条记录后运行的距离。

我使用以下代码计算运行总计：

SELECT a.run, a.year, a.date, a.distance, round((SELECT SUM(b.distance)
                       FROM vwAllCast b
                       WHERE b.run <= a.run),1) AS AccDistance
FROM vwAllCast AS a
ORDER BY a.run DESC;

此代码返回总计AccDistance中所有距离的所有记录。现在，我想每年重新开始积累。有谁知道如何实现这一目标？

Answer 1

像Piyush说的那样，我认为这样的事情应该有效：

SELECT a.run, a.year, a.date, a.distance, round((SELECT SUM(b.distance)
                       FROM vwAllCast b
                       WHERE b.run <= a.run and a.year = b.year),1) AS AccDistance
FROM vwAllCast AS a
ORDER BY a.run DESC;

Answer 2

自联接+分组可能比相关子查询快

SELECT a.run, a.year, a.date, a.distance, SUM(b.distance)
FROM vwAllCast AS a
JOIN vwAllCast b on b.run <= a.run AND b.year = a.year
GROUP BY a.run, a.year, a.date, a.distance
ORDER BY a.run DESC

SQL计算运行

2 个答案: