基数:名称,费率,dt。每天插入成本,我需要知道没有第一天的最大成本。所有产品的第一天都是不同的。
包含所有日期
SELECT `name`, MAX(rate) AS max
FROM `base`
GROUP BY `name`这类似于我想要的,但不起作用。
SELECT `name`, MAX(rate) AS max, MIN(dt) AS min_dt
FROM `base`
WHERE `dt` > `min_dt`
GROUP BY `name`示例基础
skirt, 6, 2018-10-10 00:00:00
skirt, 7, 2018-10-11 00:00:00
cap, 7, 2018-10-11 00:00:00
skirt, 8, 2018-10-12 00:00:00
cap, 6, 2018-10-12 00:00:00 需求
skirt, 8
cap, 6发布于 2019-03-07 23:59:11
一种方法是使用内联视图来获取每个名称的min_dt。然后,我们可以连接和排除最小日期行
如下所示:
SELECT b.name
, MAX(b.rate) AS `max`
FROM ( SELECT d.name
, MIN(d.dt) AS min_dt
FROM `base` d
GROUP
BY d.name
) m
JOIN `base` b
ON b.dt > m.min_dt
AND b.name = m.name
GROUP
BY b.name还有其他查询模式可以达到相同的结果。我的偏好是避免相关子查询,但是类似下面这样的查询也会返回指定的结果:
SELECT b.name
, MAX(b.rate) AS `max`
FROM `base` b
WHERE b.dt > ( SELECT MIN(d.dt)
FROM `base` d
WHERE d.name = b.name
)
GROUP
BY b.name(对于这两种查询表单,如果给定name的base中只有一行,则查询将不会返回该name的行。)
发布于 2019-03-07 23:59:51
您应该尝试使用子查询排除最小dt:
SELECT name, MAX(rate) AS max
FROM (SELECT name, rate, dt
FROM base B
WHERE dt NOT IN (SELECT MIN(dt) FROM base WHERE name=B.name )) as A
GROUP BY name小提琴here
https://stackoverflow.com/questions/55047778
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